I love how many variations of the pokemon superstition there are - some people hold down+b, some hold just b or a, and some people mash it repeatedly. Personally, the one I always heard (and what I can't help myself from doing to this day, even though I heard it back when there were only 151 pokemon) was that you had to hold b after the third "shake" and it would help keep it from popping open.
I also still avoid cracks, and I'm not a fan of walking under ladders, but that one is more just because I worked construction, and I've seen enough heavy things fall from ladders to give them a wide bearth.
I also have a bad tendency to talk to/attempt to reason with inanimate objects. Not sure if it counts as a superstition, but I'll try to psyche up or bribe my dice if they're rolling badly, yell at whatever object I stub my toe on for jumping out in front of me, or threaten electronics that aren't working correctly that I'll throw them away and buy a new one. Even though I know it's bs, I swear it seems to work with the dice and the electronics.