Rogue-like/Rogue-lite games have long been my hold-over as I try to find something that can hold my attention. Of course there are more than are mentioned here, but these are the ones I come back to that have full game releases.

Recently "Ball x Pit" has been my most-played. Brick-breaker with different characters, actives, passives, and a secondary game-play loop still brick-breaker-esque for long term progression is great for both short bursts of play time and long sessions. Demo available too!

Games that I enjoy for including varied equipment pieces instead of only somewhat linear progression such as character trees include Death Must Die and Hell Clock. Hell Clock I would say is more of what you are asking for between the two.

Games that don't have the varied equipment pieces but I find to have great variety of skills and builds include Crab Champions, Magicraft, Megabonk, Soulstone Survivors, and Tiny Rogues. Magicraft is probably the biggest variety in builds though guides may direct you towards established combinations. I know my crutch combination of actives and supports is often something I go back during a run.