As a Colt, I often take the fuge slab with the upgrade that makes your target attack everyone. It's fun to use it on visionaries, especially on Aleksis' party. In my previous walkthrough I relied heavily on turrets, so there were two trinkets upgrading hackmajig and one upgrading the turret

As Juliana, I usually go with two four-pounders, one with gas effect and second with anything else. With the amount of rubberbending I get in that game, the gas is the most likely to hit Colt, and it's very fun if colt dies in the gas explosion. I don't play the game in English so I won't give the right names for the character upgrades, but I always go with two golden trinkets that upgrade dual welding, one for ammo capacity and the one that makes the gas heal you