What is the best farming spot, you guys have used?

Check your Grimore to see where (Old Russia, Sea of Storms, Ishtar Sink, etc.) materials are most likely to drop. Patrol there. Kill as many enemies as you can. (IMX, the more enemies you kill between engram drops, the better the drop is likely to be. Especially if you've done it quickly. Equipment/engram drops don't tend to happen for ability kills, so you can charge up your karma meter a bit.) Farm resources while farming enemies and fulfilling bounties (you'll need them to upgrade your 20+ equipment). Do lots of missions. Join every Public Event you come across. Look around for chests, realize that opening one generally causes another one to appear somewhere nearby. (Some people are obsessive enough to plot out the chain. I'm not one of them. But I'm certainly not above opening a half dozen chests in a couple of minutes.) Most of my best gear has been gained from patrols. If you need glimmer, check out your Grimore again and see what enemies will drop the most when you use a consumable. Find a place where you can farm that type of enemy. If you're Playing Viper or Wolf Vanguard Strikes, it seems you'll get sent to Earth and Venus Strikes a disproportionate amount of the time. Both have great farming potential if you use a consumable, you get to gain rep and vanguard marks at the same time, and dropping a lot of enemies causes a lot of equipment drops. My favorite place is on Venus. Go left from the spawn point to the open area with a lot of Fallen. Fight your way across the open area, up the ramp, then jump down and start over. Repeat until you get bored. There are a lot of small caves in the area, so chase the chest as you go. Collect the Spirit Bloom that tends to appear near the caves.

Venus

Venus