Top 20: I also have number 18.
SNES:
EVO : Search For Eden
Harvest Moon
Chrono Trigger
MegaDrive:
ToeJam and Earl
PS1:
Team Buddies (Didn't know this was classed as rare, I loved this game to bits. Foul mouthed pills with arms and legs and really good game mechanics.)
Bust a Groove
Dreamcast: (Still one of my favourite consoles)
Marvel Vs Capcom 2
Powerstone 2
Skies of Arcadia
XBOX:
Jurassic Park Operation Genesis
Sniper Elite
Jedi Knight Academy
GTA Trilogy
Fatal Frame
Star wars Battlefront 2
Star Wars Knight of the Old Republic (1 and 2)
Baldurs Gate Dark Alliance 2
I have quite a collection. I had the original Samba De Amigo for the dreamcast in it's box with the maracas that i only used twice. I got rid of it a while back to a charity shop after cleaning up my house. Didn't realise that they are quite rare and some have sold upwards of 3-400 quid. Gutting.
I quite a big games collection and i'm sure i have a few more rarities than the ones shown on this site.