I'm super-late to the party (and my first-ever jam), but I'm planning on making my entry focus on Musical Instruments (I actually have an idea for a suite of musical-themed L&F games), as they pass on from musician to musician! It opens up a whole can of worms for time-frames and settings, but I also think it would allow a playthrough to go from the Renaissance all the way up to modern-day, and beyond (ideas/tips/tricks/thoughts welcome)