"Raider Gangs Extended" is the last one I tried out, but that was before SS2; I wouldn't trust it now with where its hand-placed 'custom gangs' are put - there's at least a half dozen manually placed spawns of them in Concord alone.
None of the other ones I've tried were even worth remembering the names of.
I actually made a "mod" myself now that all it does is tweak their armour and weapons leveled-lists a bit. (it actually merges the leveled lists of every other base game and DLC factions into the generic Raider one, so their gear is now 100% random, and as long as it's near the bottom of the load order even includes other mod-added stuff)
I haven't published that anywhere though. It's in my pile of partly-formed projects that may or may not get folded together into something useful once the SS2 Addon Maker's Toolkit gets updated with the Chapter 2 stuff.