A lot of the USAF tankers had callsigns based on money. Peso, Dollar, Franc and Quid. I suppose because going to the tanker was a bit like going to the bank. The Mildenhall tankers still use Quid I think.
Our Squadron callsign was often Lion due to a lion being featured in the Squadron badge. On exercises in the far east, it was sometimes changed to 'Ryan' to make it easier for the local controllers to say!
'Flash', gulf based USAF C130s amused me - some irony there perhaps!