Artificers
A fun one here from the UA Artificer class reveal document (which was a playtest document, and there have been updated versions):
The artificers’ drive to invent and expand their knowledge creates an intense drive to uncover new magic discoveries. An artificer who hears news of a newly discovered magic item must act fast to get it before any rivals do. Good-aligned artificers recover items on adventures or offer gold or wondrous items to those who possess items they are keen to own. Evil ones have no problem committing crimes to claim what they want.
Almost every artificer has at least one rival, someone whom they seek to outdo at every turn. By the same token, artificers with similar philosophies and theories band together into loose guilds. They share their discoveries and work together to verify their theories and keep ahead of their rivals.
Artificer rivalry is at the heart of my fics with these characters! This inspired some of the characterization and conflict.
There are also artificer subclass supplements that I've used to give the characters more background and duty. Since we know of at least one artificer subclass title in the game (Philomeen is a Sapper, and there is a supplement for this subclass), I thought it would be fun to try to assign other subclasses. I typically only look at slightly more official texts for this kind of thing, but if an independent game designer/developer has come up with a good idea I want to include I'll probably credit them for inspiring characterization!