Any condition build really, and you’ll probably want to use P/P or P/S depending on your preference. If I’m using grenades I like them with a lot of Rampager gear, because they do hit pretty hard as well and the 3 hits per attack is great for crit procs, but they work with more condition damage as well.
HGH is good for adding more condition damage and upping your power as well, one popular build is 30/x/x/30/x. The extra 10 points could really go anywhere. You want to get Grenadier and HGH if you’re into the Grenade Kit. You could also focus more on pistols and go 20-30 points in Firearms. FT/EG builds are popular as well and can do good condition damage, something like 10/20/0/20/0, again the extra points pretty much wherever you want them.
As for utilities, any of the elixirs really as their job is to buff pretty much any setup. Elixir U is very strong in PVE. FT is ironically more about power if you’re using it as a main weapon, but used as a utility it’s pretty solid in condition builds. EG is very good, the auto attack is surprisingly strong for condition builds. Bombs are great for fields, not a ton of condition damage besides #2 though, and of course grenades. Turrets (if they ever fix the attack duration bugs) are good as well because the condition damage they do scales with your condition damage stat. So Flame Turret, Rocket Turret, Rifle Turret, all will do pretty solid condition damage for you while you unload with your pistols or something. I’m not a big fan of turrets, I think they need a big rework, but it is an option.
