Is it illegal ?

You know he got them fraudulently, then you are involved and could be liable to a conspiracy charge. Stay clear.

There is a charge called receiving stolen property.

I know a guy who bought guns from someone who stole them after his neighbor gave him the key to the house to prevent anything, especially the guns-from getting stolen. The guy who bought the guns knowing they were stolen went to jail for several years, even though he wasn't in on the theft.

What if I sell them to someone else ?

They will have no title to them.

In that case you are probably in even more trouble. You might want to contact a lawyer on this. How old are you and this someone who committed credit card fraud? If you're under 18 I suggest you fess up and go to your parents, get a lawyer, and go from there.

Do you mean, "What if I bring more people into the ongoing crime and get them implicated on the stolen property/credit card fraud crime ring?"

Your only hope for reprieve/leniency is to turn in your alleged friend as well as the questionable tickets. You just might get off scot-free.

One more thing-get a lawyer and turn yourself in even if you already sold some to somebody else, or promised to. Whatever you might have done already, the sooner you remove yourself from this crime, get legal representation and turn yourself in, the better it will be for you. I would get a lawyer today, if possible.

Handling stolen goods normally gets harsher sentencing than theft, that's because there's less likelihood of getting caught. If you do get pulled they'll check your internet history, and this thread will pop up. Leave well alone.

What about a right bollocking for shooting from the hip?

Bollocking is a civil matter.