Star ocean: Blue sphere

Neither are super rare but it cost me a bit to get my hands on them. I've played rarer games using emulators but these are the rarest ones that I own.

Enix FTW!!!

Thrill Kill, on a modded PSOne. The game never saw release, but was still possible to get on certain internet websites for a while.  You can't really go much rarer than that.

If I must mention a game that was actually truly released, then it's Tobal 2, on that same modded PSOne. xD

Uhm,I don't think that I've played any game that could be considered ''rare''.

High Five!

I've got an NTSC copies of loads of rare not-PAL localised PSX RPG gems and Valkyrie Profile was the most expensive, followed by Dragon Quest/Warrior VII and Tales of Eternia/Destiny II.  It is an epic game, love the battle system.

Panzer Dragoon Saga, it was my dads and he never left it with my collection of Sega Saturn games, it was a good decision as I usually lost my games or put them in the wrong case.

Action 52 on SEGA Genesis:

Take no Prisoners on PC:

The Mummy on PC:

EDIT:

The Fifth Element on PC:

That's all I remember... for now.

One Piece: Unlimited Adventure for the wii is the most rare that I have

Probably the game that I have as an avatar: Shining the Holy Ark.
There might be an even rarer one, I'll have to look through my collection, but this is one of my most loved games ever and it just sprung to mind.

Knights in the nightmare. Amazing game, good difficulty, nice story, amazing/weird gameplay... I loved the art of the game.