Although Juniper is owned by Barclays, I'm not if all their credit cards are the same. I just got approved for the Choice card and the email told me to go to a Barclays site to manage it, while my existing Best Western card is managed at the Juniper site instead.

So if they're separate, add Juniper to the list: Best Western, Frontier/Midwest Airlines (dunno if they still have separate cards or not, since these airlines are merging), etc.

Also, BofA has one or two airlines left, despite dumping two of their hotel cards (which Barclays picked up).

The issues is not which card companies have bonus offers. The issue is which card companies have airline or hotel cards, or points program that allow transfer to those. If they have a card for a real miles or real hotel points program, it's virtually guaranteed they have some sort of sign-up bonus for it.

Stand-alone transferrable points are more iffy. Some AMEX MR cards sometimes come with a sign-up bonus, but not all always. And Diners Club (US/Canada) hasn't had a sign-up bonus in several years, but then (1) it hasn't been taking new apps for personal cards for a year or more, pending the sale, and (2) it's in the process of being sold by Citi to Bank of Montreal, but the BofM hasn't taken over operation completely yet and thus we don't yet know if they'll offer sign-up bonuses for Diners yet.