I guess you mean Fan Token such as PSG token, Barcelona token, City token, or the like. These tokens are associated with the clubs, they are official tokens. Regarding the functions, I think it depends on the club itself. If it is possible, the tokens may be available to get products/merchandise or to vote on certain decisions. Actually, the concept is interesting because it has the advantage for the clubs and the fans. However, I think it is still not so popular until now and the prices of the tokens are too volatile.