There's no other real way to get AGR points via credit card spend other than the BoA card currently. As far as I'm aware there's no program that transfers into AGR; certainly no credit cards or airlines. You could hop through the Choice Hotels program if you can get points into there, but the conversion rate is terrible (32,000 Choice points becomes 5,000 AGR points - quite the drop!) The points.com loyalty wallet also shows four programs, the most notable being IHG, but even there the conversion rate is terrible (75,000 IHG points becomes 10,000 AGR points.) None of these are what I'd consider to be even remotely useful transfer partners, unless you have a bunch of points stuck there that you will absolutely never use.
You can earn points through surveys and through the AGR shopping portal. It's also likely that a new card will be announced "soon," though when is anyone's guess. If you have one of the BoA cards already you can still earn points via spend, and there's been no official end date announced for that yet, just rumors and speculation.