We have a "loyalty card" from PF Chang's ( Warrior Card). A little different because it is not BUY X and GET X... they change around what you get ...right now it is a free order of lettuce wraps. I like the offers, YMMV.

Also have one from Carraba's....it is called Amici Club. Their's is a little different than most, too - you get emails w/ offers and specials. Not very lucrative, but still....we have been invited to (3) different tasting occasions where we tried new menu items, etc when the restaurant was closed and only Amici members were invited.

As another mentioned - the McCormick and Schmidt one - good news is that if I can host a lot of business dinners there, the points add up fast...but their points expire, which is always a big turn-off for me. Especially as they offer some pretty neat top tier rewards...but most people's points expire before they accrued enough to use them. The free appetizer each trip is nice though...and we do find we can more easily get reservations (and snugs!) when we mention the card.

We have also started taking advantage of the gift card "Buy $$$ and get $$$ free" - available at Christmas of course, but also around Mother's Day/Father's Day, etc. (and in some cases on line all year). Often a 10 - 20% savings, but of course you are spending your money up front.