That’s rather a build-specific question.
- For a Deputy Build ( which uses Jakobs ) you need a very specific mag size ( just enough so you have two shots before reloading ).
- Hyperion shotguns are always great - good fire rate and accuracy - bad with Steady as She Goes though.
- Bandit’s are nice because of their mag size and Keep Firing’s ability to fix their poor fire rate and reload.
- Tediore can work.
To answer your general question, I never keep any gear below level 50. At that level however, you can get some great gear that may be a pain to farm but can serve many characters well into UVHM. I’m referring to quest rewards or farmable items that have a quest as a pre-requisite ( I hate the Clan Wars quest, so if I have toon that’s done it I’ll just use that toon to farm a Slagga / Maggie instead of running the quest again ).
Items that come to mind are slag weapons and the odd relic : Rubi, Fibber, Pimpernel, Slagga ( all slag ), Sheriff’s & Deputy’s Badges.
The most important bit of advice is not heeding anyone’s advice and just trying everything out! Change your gear every hour!