Whatever's near it's sell-by date and priced down at your local supermarket is a good starting point!
Putting "Cheese" and "Cheesepaste" into this forums search facility is another.
Fashions change - Edam used to be the big thing, now nobody seems to use it - has anyone told the fish? As Les says, experimenting is all part of the fun, chub will take anything from the blandest processed plastic cheese to the fieriest nine-year-old danablu, knock up a few in the kitchen - with additives like garlic, marmite, chilli, and any other culinary or bait flavours you can find.
Hot hint - Label them!!! If one works better than the rest, and they all look the same....