Amphenol connectors. Used a ton in industry, military and aerospace. They are actually really nice when you get down to it, but you need expensive tools and the connectors themselves are usually quite expensive. I once had a client ask for a specific 6 pin one, only about the size of my thumb, it was $800.
Someone else mentioned Habitica already, there are a few out there. I think they usually call it gamification. The only one I tried and was able to commit to was Walkscape (specifically gamifying getting out), although I’ve been slacking due to nasty winter weather.