What are some games with characters... from other games?

Along the lines of Cannon Spike, Neo Geo Battle Coliseum, DreamMix: TV World Fighters, Super Smash Bros, Marvel vs Capcom...
But also as small as the Spartan in DOA 4,Dante in Viewtiful Joe.. 2 and the Ratchet skin in Jak X?
I know there's bound to be possibly hundreds more, but these are the only ones I've ran across.

My brother and I've just been enjoying games with characters from other games, lately. They feel special or something~
So I'd love to know a few others. n.n
Thanks for your time.

Dante appeared in Shin Megami Tensei: Nocturne.

Chun Li appeared in Breath of Fire

Samus appeared in Super Mario RPG

Cross Edge had characters from many games, including Darkstalkers.

Super Robot Taisen Original Generation: Endless Frontier had KOS-MOS from XenoSaga

The cross or versus games don't count, Marvel vs. Capcom has Marvel and Capcom characters in it... isn't that the point of the game? Something like X-Men: COTA would work because it has Akuma in an X-Men game. There isn't supposed to be a crossover there but there is. Or maybe something like Final Fantasy Tactics on the PS1, Cloud and Aeris are in the game when the game isn't set in FF VII's time or setting and it isn't one of the dozens of games based on FF VII.

Onimusha: Blade Warriors had Megaman and Zero as unlockables. It becomes a WTF moment too, since its the GBA Megaman and Zero on a PS2 game.

There is that Tertris ending that has Samus playing a cello.

cloud is in final fantasy tactics for the ps1.keohane122

There's also Itadaki Street for the PS2, which has characters from FF and Dragon Quest. Too bad its exclusively sold in Japan.

Vyse, Aika, and Fina from Skies Of Arcadia can be selected as playable characters in Valkyria Chronicles.

In Shenmue, you can collect small toys based on some of Sega's most notable franchises.

Oh, and Kratos is to make an appearance in the latest Soul Calibur title coming for the PSP.

In Jak II you can find a billboard in Haven City with a picture of Rachet from Rachet and Clank on it.

Lo Wang: Shadow Warrior has a cameo of Lara Croft...she is dead in the cameo, but hey she is there

I forgot all about Chun-Li in Breath of Fire. Wow that is old school.

I'm sure you'll love Kingdom Hearts because there you'll find lots of characters from FF making cameo appearances in the land of Disney. BladesOfAthena

gta san andreas claude from gta 3.

doa 4 spartan from halo and ryu from ninja gaiden

ssbb snake from mgs 4

dunno if it counts, but there were those spyro the dragon/crash bandicoot crossover games on the GBA