Almost everyone has changed their favorite 3 several time, so any kind of apple / crab is good to talk about.
Everything I got is young, but I need zone 3 for camp. My picks there are 30-06, courthouse, and Violi's crab from SLN. I got winter wildlife and AWHO from them but AWHO is biennial and winter wildlife behaves alot like 30-06. Winter wildlife has been tough bugger to graft. 30-06 you could graft on anything. Easiest one to take from what I have done.
yates, keener, and kerr are commercially known 3 picks for late trees. Turkey has all 3 of them.
Best by far way to graft is fresh off the vine. Got some unpruned low branches on 30-06, crossbow, and chestnut. Ordered P18 to try out at camp. Also got a few m111's I thought wouldn't do well up there, but might as well try it out. G890 are experiments for the house. I got a franklin cider on b118 doing well at home, giving those a try at amp this year too. I'm not sure if I would recommend franklin, seems so-so. But, its well known and can survive polar vertex's in northern VT. Im not too far away in NY.
One I think will be great for folks in dry areas is arkansas black x dolgo. I am digging up my young arkansas black though. Roots are loose. Going to topwork a branch or two on my dolgo from turkey creek. I think he has a more speciial variety that drops a bit later. IF they meld together good, that'll be a cactus of an apple tree. Future of deer apple trees might be more environment than