D&D
Star Wars
Earth sea
H.Potter
Magic The Gathering
Marvel/ D.C
D&D - Some of my classmates got me to join their AD&D 2e game in 7th grade (when I was 12 or 13) circa 1993. With a short break around the time I moved countries at the beginning of the century, I've been playing D&D ever since.
Star Wars - Sometime in the 80s. I was born in 1981, so I was too young to see any of the OT in the theater, but I got to see them plenty on VHS.
The Phantom Menace was my first experience getting to see a
new SW film in the theater - and what a letdown that was! Nevertheless, SW is probably my favorite geeky thing outside of D&D. I'm really loving
The Bad Batch and am very much looking forward to S3 of
The Mandalorian.
Earthsea - I know it's a series of fantasy books but that's about it.
Harry Potter - I deliberately avoided the HP books in the 90s. Didn't read the books or watch the movies until my children wanted to in the past decade or so. I've been less than enthusiastic about HP-related stuff of late.
Magic the Gathering - I know what it is, and while I have bought all three MtG D&D crossover books, I have never played the card game and have no desire to do so.
Marvel / DC - I read the odd comic / watched the odd movie (e.g. the Tobey Maguire Spiderman movies and the older X-Men movies) as a youngster, but I didn't "get into" the MCU until we subscribed to Disney+. I think the only recent DC movie I've seen is
Shazam!
Other big-name geek stuff that I may have left out.
Star Trek - I got into ST around the same time as D&D if not a little earlier. I got hooked in with TNG. Watched DS9 and Voyager but haven't watched any ST TV series since TNG ended. (Tried watching the original series but found it too comically dated for my tastes so gave up partway through.) I have watched all the movies, though. As much as I like ST, I think I prefer SW these days.
Middle Earth - I would have been introduced to the books as a child in the 80s. I remember liking the old Hobbit and Lord of the Rings cartoons. I read the Silmarillion a long time ago. I enjoyed Peter Jackson's films, including the Hobbit trilogy. I haven't watched the recent show (and am not sure I want to given the reviews).
Game of Thrones - A friend got me into watching the show after S1 had finished but before S2 had started. Watched through to the disappointing ending. I mostly enjoyed S1 of House of the Dragon. I have not read any of the books and have no intention of doing so (since it's unlikely GRRM will ever finish the series).
Foundation - I love the original trilogy. The later books are rubbish. I have no intention of watching the show.
Dragon Age - I love, love, love the world of Thedas. I've played (and enjoyed) all three PC games and am optimistic about the upcoming fourth one. I've also watched the Netflix cartoon series and enjoyed that. I haven't read any of the novels. I own the original three TTRPG box sets but haven't gotten to play the game ever.
Video Games - I started gaming with an original NES back in the 80s. I currently have an old N64 and a second-hand Wii. Haven't moved on to the Switch and don't really want to as the few times I've tried it, the games have been too flashy and visually overstimulating. Never got into any of the other consoles (e.g. Xbox, Playstation, etc), as I prefer playing on a PC. I also prefer single player over multiplayer.