Is there a Clan-Domain?Koeln, )
I don’t exclude that .clan may exist at the alternative DNS root service providers.
You need to download a plugin for using the alternative DNS root services, your customer must know, that you use an alternative DNS root service and must also download a plugin. This is the cause why some experts think, that domains of alternative DNS root services should be evaluated as a kind of domain scam.
ICANN will open a next round for New Top Level Domains applications during the coming years. It is possible, that a company applies for .clan.
You may consider the Team-Domain, Game-Domain or Games-Domain as a solution for your needs.