I remember years ago people used to pay you to use a certain signature.
Is this still a thing?
Which company pays the most?
Yes, still a thing, you can still be paid for a signature campaign in this community. Depends on each rank though, there are campaigns that still accepts a member position and up. There are campaigns that only accepts Hero-Legendary.
I don't know which campaign pay the most, but in a average, minimum for a Hero could be around $60-$75k, and for a Legendary, could be $100 tops.