Nitrobetting has a sports bonus and nice loss backs in the NFL up to 15%.
Most popular sportsbooks have their own variant of cashback for losses suffered in a given period. Usually for the week that has passed. Some even have cashback and count all money wagered, not just the losing bets. But I don't know which ones do that.
Betcoin has 2 lines and boosts. You can get more than 1 boost.
What do you mean with 2 lines, what does that mean? How many bet boosts per sport and per day are we talking about?