Yes, there is. The Creator of Thorn... Dread'kin Yore..? I think thats his name. He was a hunter that was tainted by the darkness and created Thorn. The Creator of The Red Death. Was notably bad, and killed Guardians including their ghosts. The first Iron Lords had earned their fame from bringing "warlords"; guardians that had used their power to subjugate and control normal humans. To justice. Notably bad Guardians were normally either Hunters, because of the risky nature of their scouting missions, and seeing the darkness up close. Or Warlocks, because of their studying of the darkness, Vex, Hive, or otherwise.

Anyone that asks for 305 Only in their LFG posts are bad guardians.

Dredgen Yor was straight-up corrupted by Hive influence. Osiris......could go either way. Kabr......assuming he hasn't just ceased to exist then whatever's left of him is probably not pretty. Toland the shattered is a lot like Osiris, he dove into some really dark stuff and Traveler only knows what's gonna come back out. The Iron Lords apparently had to deal with a bunch of tyrannical warlords back before the city was built. Dredgen Yor apparently has some sort of Reaper-main fanclub following in his footsteps who insist that they're TOOOTALLY not gonna be corrupted bruh. Guardians may be blessed with power and limited immortality, but make no mistake - they are just as fallible and imperfect as anyone else.

There were lots of tyrants way back in the Dark Age before the Iron Lords formed to dispel them. Literally, the Iron Lords were first made by a mutual want to quell and destroy rampant and evil 'guardian' tyrants. From then on, you've always had several that turned away from the City. Fewer still that actually turned to the Darkness, but they're there. Ryzel became Dredgon. Toland became essenctric (spelling ?) and raving and basically sacrificed his fire team (intentionally or not, is your opinion) to get closer to the songs of death when they went after Crota. The wielder of Red Death (not sure if given by name) murdered several guardians permanently, causing the Vanguard to ban the weapon entirely (obviously, more of a lore standing than anything else). Osiris famously left the city and the vanguard in pursuit of the Vex. Saint-14 had his own crusades more closely tied to the speaker than he ever did the City or vanguard. Not sure if that's 'not caring' but it was a different direction in the least. -- Ah yes, upon reading a few comments you could also add Sunbreakers to the list. They aren't evil, but the aren't necessarily defenders of a homeland either. Sunbreakers used to be under the guardian realm of power until the few Sunbreakers left and became their own order. They were called upon or could be bartered with, but were not under order of the Vanguard or the speaker and could easily refuse a request if they wanted to. I think they were mercenaries at one point too. I also believe that the Sunbreakers, for a time, were feared rather than looked at as a potential ally. They also take their title very seriously. If you read the D2 'lore' tap on the Warlock Sunbracers (used to be Sunbreakers) you see a converstation with a Warlock and someone else about how the Warlock refuses to call his Sunbreakers 'Sunbracers' and is aptly replied to that he could end up getting killed by the real Sunbreakers if they overheard such a use of their name. Obviously, since all Warlocks are badass af, the Warlock didn't care. Back to the point. No Sunbreakers were really tied to the city, at all, for a long time. That is, until, the Fallen attacked most famously (twice). I believe the Sunbreakers helped with that fight immensely but after the fight they did not stay, yet again. Only until the Vanguard (you) had regained the knowledge of the Sunbreaker way (which you did through a trial), only then were there official Sunbreaker Titans bound or under order of the Vanguard tribunal.

half the D2 community

If you’ve ever used LFG, this is a silly question. Some people are so bad you actually wonder if they are paralyzed or had a stroke or a genetic alteration where they were born without thumbs.

On top of the ones already mentioned... Osiris was considered bad by the speaker, and exiled. Lysander, possibly a Guardian in that he has a Sparrow named after him, was run out of the City for trying to overthrow the government. And before the Guardians grouped up for the power of good, many of the Guardians were despotic warlords ruling over regions. A sense of ethics did not come with the powers.

Define "bad" because you could debate guardians like Toland the shattered or Osiris (I'm waiting until the DLC to decide) aren't purely evil but not purely good. Then again we do have Dregen Yor which people have already explained below. Also back before there was a city to defend and by default no guardians instead they where called risen. Some of them went on to become warlords who terrorized people.