Gaming

Suikoden 1 and 2 (and 3-5 + tactics, but they aren't as rare), Valkyrie Profile 1 and 2, Steambot Chronicles, and Robot Alchemic Drive are the ones I know I have off the top of my head. I mainly keep the rare ones that I actually play or played in the past though; I've never been a big fan of keeping new games and letting them gather dust though I can understand the appeal.

Probably Parasite Eve or Azure Dreams

I have an Earthbound cartridge in pretty decent condition

The game of life, people don't take it seriously, but it's the rarest thing you can ever own, don't throw it away, or sell it.

Dokapon Kingdom for Wii, probably.

Free epic game store games. They are so unwanted they must be rare

Ku-on for PS2. One of those, buy a random used game at GameStop only for it to explode in price years later.

I have a DOS version of Teenage Mutant Ninja Turtles Arcade, complete in box. I have no idea how rare it is because it doesn't seem to exist on any price chart websites.

I have a copy of The Neverhood on PC. Technically it is my best mate's, but I've had it in my possession since 2001 so I'll claim ownership.

probably a delisted game such as Battle for middle earth 1 and 2, as well as black and white 1 / 2.

Ever heard of Rogue Galaxy for the PS2? It came out at the end of the PS2's. Was an RPG with gameplay like that of a Tales (Namco Bandai) game. The story was fun with great characters, lore, world design, etc. It seems like nobody has ever heard of it.

The Witcher 3

Not rare games as such but got a couple of console bundles that go for decent money with their original boxes these days

NES TMNT Bundle

SNES Action Pack with Super Scope Bundle

Panzer dragoon saga. Very fun game

The Legend of Zelda Collector’s Edition for the Gamecube

Not sure if this counts but had Fight Club for PS2. Basically a Tekken clone with characters from the movie and no real story. Fred Durst was an unlockable character. It...wasn't great.

Would you consider duck dodgers rare? Not sure. But i think maybe that one. Or conkers bad fur day

The Unreal games on Epic Games and Steam I guess

Resident Evil Gaiden, complete and in great condition. Bought it as a kid to keep me busy during a long road trip.

I have a box of atari games so most likely something in there. I do have ET

Not entirely sure of the rarity but: Tales of Symphonia on GCN Final Fantasy III (VI) on SNES Pokemon Red on Gameboy Star Ocean Second Story on PS1

Pso 1-2 Plus GC

Rule of Rose, probably.

Pokémon Heart Gold and Soul Silver both with the walkers, don’t know if they are rare but I know they go for ALOT online nowadays

Hardcopy of Star Trek: Bridge Commander with german subtitels and booklet

N64. Super Mario 64, and Zelda - ocarina of time, and a gold plated Majorca’s mask.

A yellow donkey Kong 64 cartridge.

All Pokémon from game boy color.

I think I have a copy of Amplitude for PS2 laying around somewhere.

ET on Atari

It's a notoriously bad video game.

Castlevania Symphony of The Night PS1 -black disc

Haunting Ground PS2

Rule of Rose PS2

Also have an unopened God of War demo. I think it was included with a PlayStation magazine back in the day.

God Bless the Ring EHRGEIZ - ps1 Spider-Man Web of Fire - 32x

Bomberman DS UK version

Donkey Kong II: Game & Watch. It might not be that rare. Idk.

Dragon Force on the Sega Saturn. Still one of my favorite games.

I’ve got a copy of the Wind Waker preorder promotional disc with Zelda 1 and 2, Ocarina of Time, and Majora’s Mask. Got it for like $50 at a second hand shop, probably my most exciting purchase ever :)

I recently sold a copy of Michael Jackson Moonwalker to CEX for the mega drive which was rare enough that it sold for about 10-50x more than all my other games.

Marvel Vs Capcom 2 for Dreamcast is up there, I’ve got a bunch of Armored Core games now, and maybe Metal Gear Solid Twin Snakes

I have an arcade rouge-lite style game called BugHunt that I built in Unity a few years back that I never released. So, I win 😎

Is Marvel Superhero Squad for the Wii rare?

I also have the official Wheel of Fortune Wii game and a few other company licensed stuff

Video game-wise I have Tomba! and Tomba 2 for the Playstation among other similar, somewhat rare titles.

Board game-wise I have a collector's edition of Discworld Ankh-Morpork.

Nosgoth

I own a digital Norwegian copy of The Longest Journey. It wass created by a Norwegian company, and has tons of famous Norwegian voice actors in it, but is more or less impossible to find online these days.

I have a copy of FE Path of Radiance for the GC with the original Box in super good condition - proud I at least kept that one.

Dreamcast - MoHo (PAL exclusive & rarest PAL game)

Gamecube - either mario baseball (PAL) or NCAA college basketball 2k3 (NA)

Ps3 - hyperdimension hypercollection (PAL) not many on ebay and Pricy for a ps3 game

I think my rarest is Dragon Slayer for TurboGrafx Super CD. Don’t know that anyone really wants to play that, but I enjoyed it back in the day. My old SNES rpgs (Ogre Battle, Earthbound, FF, etc) might be worth more but they’re also easier to get.

Fable for PC, Animal Crossing for GC and The Sims for PC