Hurry if you want to get in on this, as the offer expires in a few days:
The Amex Blue for Business card has an offer through the end of this month where you get 10000 bonus Membership Rewards points for first purchase, and then earn 9 extra MR points per dollar spent on restaurants (up to $2000) in the first 6 months, plus 1 extra MR point per dollar the first year, adding up to 11 MR points per dollar on restaurants in the first month. (Oh, and then annually there's a 30% bonus, but only on your base MR points.)
MR transfers to Delta, which is an RN partner. So if you do this at SkyMiles Dining restaurants you can get 5 Delta miles (once you're VIP**) from SkyMiles Dining, plus 11 MR points -> Delta miles from the card, for at a total of 16 Delta miles per dollar spent.
Two things to note about the card:
1. You don't have to have a business to apply for a business card. See this thread:
2. You will need a "real" Membership Rewards card to be able to transfer MR to Delta. The card above won't do that by itself. By a no-AF Everyday card will. So pair with that (or any other Membership Rewards cards) and you can transfer.
* Obviously, I chose Delta as the example because that's the one airline which has both Membership Rewards transfers and Rewards Network dining. But there's nothing to say that you can't do this same "stacking" by mixing one Rewards Network dining program for one airline and transferring Membership Rewards points to another airline. (It's just harder to explain "tersely" what you earn if you stack two different airline programs.)
** To earn 5 miles per dollar in a Rewards Network dining program, you have to have 11 dines in the current or previous year. Until then, you only earn 3 miles per dollar.