2 or more ribbons?

[Researcherno1]

As you know, it's not important, but how many ribbons are there in colosseum and xd?

I know there is a shadow ribbon for purifing a pokémon and a 100-streak ribbon for clearing mt.battle.

I heard something about black tower clear and red tower clear etc.

So how to obtain the other ones?

 

[Whompithian]

The other ribbons were meant to be obtained from real-life special events. They cannot be obtained legitimately within the games themselves. I don't know if the events ever took place in Japan, but I'm certain that they haven't takent place outside of Japan. So, the Overcame Difficulties and 100-Trainer Beating Commemorative Ribbons are the only two you can earn in Colosseum and Gale of Darkness.