My favorite deck I own is my Jasmine Boreal of the Seven all old border deck. Lots of vanilla creatures and an enchantress subtheme for card draw. Its fun to work within the limits of old border only, and its a great excuse to look at tons of old cards.
I have [[The Mimeoplasm]] as a "play your deck" commander instead of the usual mill and reanimate plan. Probably the most out-there card I include is [[Chaos Wand]]. This deck is really just an excuse to cast [[Villainous Wealth]].
Sometimes I think of interesting deck ideas but I'm too lazy to bother actually making a list and instead just browse cards on Scryfall for fun. I'm also just not playing nearly as much these days.