Power Troopers - Borderlands 3 Farming Guides
Location: Atlas HQ on Promethea
Part of: Rare Spawn
Drops: Surge (Grenade Mod), Tran-fusion (Grenade Mod), Star Helix (Dahl AR), Vanquisher (Dahl SMG), Hyperfocus XZ41 (Hyperion SMG), Thunderball Fists (Maliwan Pistol), Destructo Spinner (Maliwan SMG) and Nova Berner (Shield)
Power Troopers are a rare spawn which you can find in Atlas HQ on Promethea. There is also a quest you can get called Kill Power Troopers on Sanctuary, but it is not required to spawn or fight these enemies. Also, the quest does not always spawn on the Sanctuary Notice Board - it's random whether or not it is there for you and there is no reliable way to get it to spawn.
As for the Power Troopers themselves, you'll find them in the outside portion of Atlas HQ. When you go near the Typhon Log that is marked on my map the Power Troopers will jump down and attack you, unless you go over to that area they will not spawn. If you plan to farm the Power Troopers for awhile, I recommend you grab the save terminal inside of Atlas HQ that is marked on my map above. It'll save you travel time.
For loot, you have a chance to find the following items: Surge (Grenade Mod), Tran-fusion (Grenade Mod), Star Helix (Dahl AR), Vanquisher (Dahl SMG), Hyperfocus XZ41 (Hyperion SMG), Thunderball Fists (Maliwan Pistol), Destructo Spinner (Maliwan SMG) and Nova Berner (Shield). These items can drop elsewhere in the game too but have a higher chance of dropping off the Power Troopers.