I got Daze Before Christmas on Megadrive in the box which is worth $1200 AUD, picked it up for like $10 from cash converters 30 years ago and play it every Christmas as a tradition.

Next is Conker's Bad Fur Day which goes for $350 AUD now apparently.

Who knows, maybe oneday I'll need the money lmao

Anyone else own any rare or valuable stuff?

I think it's Mad Stalker Full Metal Force on PS1 and MUSHA Aleste on Mega Drive. Both roughly over $300 but prices keep shooting up I don't know the price anymore.

Snatcher for Sega CD

Never checked, but I do have a ton of N64 and GCN games. I’d imagine some of those are worth a lot. Luigi’s Mansion, TTYD, Smash Melee, SFAdventures & Assault, SM64, Zelda OoT & MM, DK64, Paper Mario 64, and so on. I’ve also got copies of Sonic Adventure 1 & 2 for DC.

I also have Skylanders Imaginators for Switch 1, which from what I recall is worth a lot. Got it during launch month of NS1, all the way back in March 2017. And some Skylanders (e.g. Chompy Mage, Wildstorm, Robow, Gold Chop Chop (series 1), Stone Roller Brawl & her vehicle (SuperChargers)) and Amiibo (Big Yarn Yoshi, Gold Mario, etc.) that are worth hundreds.

Edit— Looking at some lists, it seems Twilight Princess (GCN), WindWaker+Master Quest, Mario Party 6, MarioKart Double Dash, Majora’s Mask (N64), literally any Pokémon on GameBoy, GBA, and DS lol, and Prime Trilogy (Wii) are some of my most valuable. Neat!

I don't probably own anything particularly valuable. I can't imagine anything I own to be worth more than 100€, but I suppose there might be some small surprises. I don't have any particularly strong candidates in mind, though, so I don't think it's worth checking.