Aviation - private pilot airplane single engine land; instrument rating airplane; complex, high performance, and tailwheel endorsements; part 107 remote pilot; DC flight restricted zone; instrument ground instructor (this might be a good one for you, just take the FOI and then AGI or IGI written tests and visit your local FSDO to get the cert issued). Considering getting my commercial, multiengine, and CFI certs
Maritime - master 100 tons inland / mate near coastal plus a bunch of random crap the USCG throws on there if you get those (need to renew these this year); American Sailing Association 101, 103, 104
Scuba - just the useful ones here cause I have a whole wallet memorializing money flushed down the drain: rescue diver, ice diver, solo diver, drysuit, open circuit advanced nitrox/deco procedures, 45m helitrox closed circuit rebreather w/deco, certified Poseidon regulator+rebreather repair technician (though the big thing I learned was just to send my gear to pros working with this stuff every day). Currently my big focus is training up to take the 60m normoxic trimix rebreather course in the fall
Radio - general class ham (failed the extra by like two questions, in my defense I had only studied for general), restricted radiotelephone operator (literally just a cash payment, needed this once for a flight I had planned to Canada)
Other - authorized to perform marriages, motorcycle endorsement on driver's license, certified analytics professional (took the test on a whim and passed, it's since lapsed but I might see if they'll let me re-up it), notary public (lapsed), have thought about doing PMP since I'd be good to go on experience reqs
I started an EMT course a while back but I dropped out after realizing I was never going to be able to remain at all proficient. I'm like this with my aviation instrument rating as well, I keep legally current with it but I am pretty cautious about relying on proficiency since I'm not flying multiple times a week
Probably some others I'm forgetting but these are the big ones! I remain really impressed with your list, you've come up with some good ones...will have to think on whether I need to pursue some of them myself :-)
Also, just to clarify my verbiage on the ground instructor bit, not at all saying that you couldn't do all the other aviation ones too (and you should, they were all a blast to get) and more...just that ground instructor is one you should specifically look into because it is relatively little-known, is straightforward and cheap to get for people like us who clearly find tests easy, and offers a fair amount of practical benefits (advanced ground instructor can teach ground for ANY part 61 rating, also you don't have to retake FOI if you ever go for CFI...flight schools in my area will absolutely hire someone on a ground instructor cert alone). No intent meant to cast any aspersions or to minimize any accomplishments!
