No, the ones I mentioned may not be the only ones you need. Ribbon policy is something each committee has to work out on its own. Some conventions go very over-the-top and have dozens of them (Worldcon in particular does this).

The most likely ribbons, off the top of my head, are:

Program Participant
Committee
Staff
Volunteer
Dealer
Artist

If you want, you can also add other ribbons with more specialty functions, such as:

Guest of Honour
Chairman
Operations

As I said, there's a lot more that could be added to this list, but this will do for a start.