Niche mechanics are my jam. My favorites usually revolve around unique economies or structures that create their own depth of play.

I love genre benders and sandboxy stuff. I’d like to see something like Chaos Seed (SNES) built on or re-imagined, dwarf fortress is great for tinker-ability, and I always liked how Nethack has some deeply designed interactions even if they can seem superficial or esoteric. FFXII with the gambit and realtime-ish combat systems was always a standout too.