Since I see there is not that much activity here, I'll list the biggest things each verse has and how would they factor:
Mass Effect: I don't think the Alliance or the Council species can do much against the Time Lords. Mass Accelerators cannot harm any weapon the Time Lords pull out, such weapons are considered to be... like the clubs of caveman, considering that they consider a control panel for every star in the universe a rudimentary weapon not worth of mass producing. I don't think others like the Protheans or the Rachni are of much use. The Reapers are some of the greater threats in Mass Effect, but I don't see them even taking out a single War TARDIS without much effort. Indoctrination, however, if used correctly, could manage to turn renegade Time Lords againts their species, which would be an adventage if they manage to keep them on a mentally healthy state such as those of Saren and the Illusive Man, instead of fanatics. And that takes me to the Leviathans, as if their enthralling artifacts are powerful enough, they could obtain something powerful from the Time Lords, and I'm not talking a single individual, but a TARDIS. If they can enthrall a TARDIS' intelligence (which I doubt, but I'm not completely sure of the mental faculties of one) then It would be useful. A War TARDIS, even better. However, enthralling a Capital Ship Reaper I think is orders of magnitude below of enthralling ANY TARDIS, even an outdated one like the Doctor's. But you say, as a CS Reaper contains the consciousness of millions, even billions, of people.
Starcraft: The Terrans are at least planet busters in this universe. But they don't have access to many things above Apocalypse class nukes (those planet busting nukes), even when the marines have hax armor. The Zerg are another story, as there are billions of them, are advanced enough to warp planets through wormholes, and can assimilate species to boost themselves (hell, the Zerg supervirus turned A -blam!-ING WORM into an Hydralisk). The Zerg Overmind is a massively powerful pyschic eldritch abomination on par or below with a Gravemind, as it is able to mind -blam!- anyone within its range and control every Zerg. Then we got Queen of Blades Kerrigan, who was a massively powerful infested Terran pyschic that took control of the whole Zerg Swarm, was one or two orders of magnitude above the Terran pyschic scale and she was at the top when she was human, could create storms of pyschic energy like the Protoss and could mind -blam!- a Protoss Matriarch (Dark Templar I think) while being on A DIFFERENT PLANET. Primal Zerg Kerrigan is above even the Queen of Blades, seeing as she has now Primal Zerg DNA, pure Zerg DNA instead of the tainted one the Swarm possesses. In this state she is the most powerful psychic in Starcraft Universe, above any Protoss, and her power couldn't be measured by the Terran scale (her Queen of Blades form's power could still be calculated by the scale even if she wasn't classified). The Protoss are beings of energy with incredible psychic control who can fuse between each other to become Archons, beings of pure psychic energy. The Dark Templar faction of the Protoss control the power of the Void (if someone is more knowledgeable than me on this subject please add). The Protoss are dangerous in here because they have the tech to glass and bust planets (they should be orders of magnitude above the Terrans at doing this) and their Motherships have black hole generators. Yes, freaking black holes, much better than supernovae (Even when a supernova would destroy the star system, a black hole would shallow it with a force so great that the atomic structures of every thing would have been torn apart, not even light escapes, and the system is completely crushed). The Xel'naga are nearly an unknown but they are the creators of the Protoss and the Zerg (in fact, these two species combined would create another itineration of Xel'naga). Their structures and artifacts are powerful enough to create energy beings which have shown disintegration powers. They've got worldships, and they seem to be incredibly powerful psychics. Amon is believed to pack the power of Kerrigan's Queen of Blades form plus more, and a Hybrid (perverted versions of the Xel'naga created by the combination of Protoss and Zerg) could mind -blam!- an entire planet.
The Halo Universe is the most dangerous of the bunch due to the Forerunners and the Precursors. The UNSC and the Covenant are fodder. While the UNSC are incredibly above the Mass Effect Alliance, they are below Starcraft's Terrans (regular marines can brawl with an Spartan). The maximum showing of the UNSC is planet busting via NOVA Bomb. The Covenant would be above even the Reapers, but they are below the Protoss (their maximum showing is planet glassing. That has nothing on creating black holes, which shallow star systems, besides the fact that the Protoss can glass planets with ease and a single Protoss is above an Elite by the sheer virtue of raw psychic power and broken psychic storms). The Forerunners are more powerful than any civilization previously mentioned, they were able to shift the axis of galaxies, devolve species as powerful as they were, and use Keyships to make suns go supernova and thus wipe out star systems with ease (one Keyship soloed an Elite fleet, even when the Prophets didn't know how to operate it). They had access to the Domain, a metaphysical database of the Precursors (which was, in fact, a Precursor in itself). They could use light to build structures, including ships. Their ships were hundreds of kilometers long, and their combat skins were orders of magnitude above MJOLNIR Armor, causing visible damage to a planet from orbit. Their War Sphinxes were even more impressive, can get into space and can bust cities. They are used in continental scale bombardements and are only considered "midsized battle suits". They used light and antimatter in their hand weaponry. Their AI were advanced enough to control entire fleets and be tactical geniuses. They were able to create Dyson Spheres as habitable planets and place them in another dimension, Slipspace, which they were complete masters of. They even travelled to other dimensions. They had limited time tech, such as timelocks which could age anything to the point of death in seconds. Their maximum showing is the Halo Array, which wiped a whole galaxy of all of its life and was able to destroy the nearly indestructible Neural Physic constructs of the Precursors.
Now the Precursors. They are complete beasts. A transsentient species which was able to travel through galaxies and supossedly predates the universe, and are infinitely more advanced than the Forerunners. They created every form of life in the galaxy, including the Forerunners and Mankind. The Precursors created constructs out of Neural Physics, or in other words, thought. The structures were indestructible to anything but the Halo Array. The Precursors could change their forms and exist as whatever they wanted, be them corporeal beings, incorporeal beings... Their last form, which they are using for vengueance purposes, is The Flood. As the Flood, the Precursors can infect anything with enough biomass, including machinery, and the collective Precursor intelligence is represented by the Graveminds, which control everyone, have the aggregate of the minds of the infected and can corrupt any Forerunner AI, and pretty much mind -blam!- anyone near them. The Gravemind (or Precursor) intelligence is a metaphysical entity that won't dissapear as long as a single Flood spore remains, even if the physical body of the Gravemind is killed. The Flood has numerous forms that are very powerful troops. When a Gravemind absorbs an entire planet's biomass, it evolves into its final stage, a Key Mind. In this state, the full Precursor intelligence is revealed which lends it more intelligence than even the most advanced Forerunner AI and the ability to control Precursor technology. Here it comes, Star Roads, roads made of Neural Physics which connect star systems and are indestructible. With the Key Mind in control of them, they can be used to destroy anything from planets to star systems, and to make Forerunner tech and Slipspace travel useless (and remember, the Forerunners were masters of Slipspace). At the stage in which the Key Mind appears, its corruption of AI begins to spread from one to another. The mere presence of Flood at this stage warps the space-time continuum. The Key Mind can even project images of the infected to use as psychological weapons. The power of the Precursor to select forms is so high that the Domain, the metaphysical database of Precursor knowledge the Forerunners used, was a Precursor in its selected form.
Now, for the Time Lords. I expect that everyone knows that the Time Lords are one of the top dog races in Doctor Who. Well, their names say everything about them. They are the [i]Lords of Time[/i]. A single Time Lord isn't much of a threat, it is still superhuman due to exposition to the Time Vortex. Most Time Lords have demonstrated psychic power, The Doctor and the Master have mind controlled people, erased their memories and read their minds on multiple ocassions. One individual Time Lord, Salyavin, could control the minds of every individual in the universe. The physical faculties of a Time Lord are beyond those of humans as well, but not by much. Technology, oh GOD, now shit gets real. Their tech granted the Time Lords mastery over time. Their ships, called TARDIS, were massively FTL ships which could travel through time and space. They could travel between galaxies and to every place in the Universe nearly instantaneously, and they could travel to any point in time, past and future. They could manipulate and change events on a whim, making the Universe their domain.
The shields of a severely outdated TARDIS (The Doctor's) were able to resist without scratches the onslaught of every horde of Ghengis Khan, Dalek beams (which shatter windows designed to withstand the impact of meteors) and a -blam!-ing black hole. It could also resist being in the vicinity of a supernova unscathed and the assault of a Dalek saucer, which has planet busting weaponry. A TARDIS' chamaleon circuit lends it the ability to change its physical appeareance into whatever the Time Lord pilot pleases, and it can mess with the minds of people to translate their language and yours in turn. A TARDIS is in fact a living being, which are grown by the Time Lords. Highly intelligent beings in fact, they share a connection with its owner, and if the Time Lord owner dies, it will commit suicide. Time Lords themselves have the ability to Regenerate, meaning that if you kill one he will resurrect in whatever physical shape it wishes, while always humanoid. A Time Lord can do this up to 13 times before killed permanently. The Time Lords also have Looms which they can use to mass produce members of their own race. When a Time Lord dies, the others upload his mind to the Matrix, a supercomputer in Gallifrey that, apart from being one of the best computers in existence, contains a microuniverse in which dead Time Lords hang out with each other. A living Time Lord can access the Matrix using the Crown of Rassilon, but only its consciousness accesses. To be given physical access, the Key of Rassilon must be used. The reality of the Matrix is completely maleable to the will of the inhabitants. The Matrix is a nearly omniscient computer that stores info from the past and can predict future events, but even then it can be by passed by someone like The Master.
Time Lords could also evolve other beings into TARDISes, and could create humanoid ones. A normal TARDIS has no weapons even when it can make a star go supernova with ease. A War TARDIS is a TARDIS prepared for war, and thus has weapons on it. It had bombs capable of piercing the space-time continuum and reduce large asteroids to rubble, Time Torpedoes that could freeze and enemy in time for centuries. can disable other TARDISes and draw them out of the Time Vortex while travelling, shoot Artron energy (the energy of the Time Vortex) blasts that can kill Eternals (a Q level reality warper) and Chronovores (the same as the others only that these eat universes as food) at point blank and a Time Destructor, which can erase a whole star system FROM HISTORY. TARDISes travelled through the Time Vortex, a separate dimension constituted of Artron Energy that the Time Lords themselves created. The TARDIS possesses a Heart, which is the Heart of the TARDIS as in the living being it is. Looking into it allows the TARDIS to mess with you in whatever way it pleases, from reverting you to a fetus/egg, or "other things". Literally, the last human who looked into the Heart (a regular 19 years old girl) got an overdose of Artron Energy from the Vortex itself and became an omniscient reality warper that could see everything in time and space, could scatter things across time and space and could reduce a Dalek fleet and millions of Daleks to atoms with a snap of her fingers. The energy was burning her from the inside and she would have died. The Doctor also had to regenerate after taking all that energy, showing that Time Lords aren't resistant to it. TARDISes could also travel between universes within the Who multiverse with ease. A single TARDIS (an outdated one) autodestructing would make every star in the universe go supernova at every point in time, erasing the universe from existence. Two TARDIS materializing in the same place could create a hole in space and time the size of Belgium.
Apart from TARDISes, Time Lords have MUCH MORE time tech. They can put planets in a Time Loop with a hand gesture. They had the Hand of Omega, a universal star manipulator that could make stars go supernova and collapse them into black holes, but they considered this rudimentary. They were able to Time Loop the Great Attractor, yes, that supermassive black hole in the center of the Milky Way, which in truth was a mad supercomputer capable of calculating every possibility in billions of universes. They had perfect Time Locks, so they were able to shut off a region from space and time. They, to punish criminals, either vaporised them, reversed their personal timelines so they never existed to begin with, or throws them into a universe in which every thing is the opposite (in that universe Anti-time exists). They have a weapon called the De-mat Gun, a handgun which erases the target from existence, by rearranging the universe in a way that it leaves you out. The Moment is a weapon that takes this to a greater scale, as it can affect an entire galaxy with this effect, and even create time locked pocket universe to trap whole civilizations.
Now, Rassilon. Founder of Time Lord society. This guy used tech to remove the energy core of a star collapsing into a black hole, time looped it, and created the Eye of Harmony, the single thing powering every piece of Time Lord tech, including TARDISes (which contain lesser replicas of the Eye). This Eye could be used to rewrite the laws of physics, which the Time Lords can do. They created the universe as it is this way. Thanks to it, they created the Web of Time (which is Time itself), the Time Vortex, and the other laws of physics. They even wrote MAGIC out of existence using the Eye, along with their own irrationality, which became the universal+ powerful Carnival Queen. The Eye could make someone omnipotent in the universe it was, like Omega was made. Rassilon found a civilization in another universe which could be a threat to the Time Lords. In response, he trapped their entire universe inside a box, created a time looped catastrophe to keep it clean inside it, and then kept the box in the basement. With his gauntlet, Rassilon could disintegrate people and rewrite the DNA of the whole human race.
The Time Lords threw the universes they didn't like inside a dimension created by them known as the Axis. They made someone an Overseer over them that was omnipotent within the Axis. They even have a universe destroying weapon named the Armaggedon Sapphire. With some tech, the Time Lords are able to become living ideas by sacrificing their forms, known as the Celestis, who live in a dimension made of thought and can plant ideas in the subconscious of mortals.
The greatest weapon of the Time Lords, The Ultimate Sanction, could destroy the MULTIVERSE and ascend the Time Lords to beings of pure consciousness. Gallifrey, the planet of the Time Lords, is surrounded by a Transduction Barrier and a Quantum Forcefield, which makes Gallifrey be impenetrable as its own space-time continuum, and requieres more than the energy of a universe devouring Chronovore to break. And that's not all simply the most important. Not black hole carrier ships, or soldiers made of living metal, and Faction Paradox feats. If you wish, I'll write on them.