Also zone 3 (Minnesota near the Canadian border), and pretty new to growing things like fruits and nuts. I have few established trees, with the exception of one very old apple that I believe is a Haralson and has been here since long before I was. It does phenomenally, even through horrible weather. I've never had a failed crop in zone 3b, regardless of weather.
I have other apples but none established enough to recommend yet. The same goes for plums and pears. And the Manchurian apricots.
Other fruits and nuts I grow include:
Hazelbrush (productive, but the squirrels love them)
Red raspberries (wild, and the cultivars Latham, Boyne, and Killarney)
Serviceberries (no known cultivar, but my wild ones have been selected for fruit quality)
Highbush cranberries (I live in a swampy area and these guys love the permanently wet areas)
Blueberries (wild and both low and high bush varieties like Northblue, Chippewa, Superior, and Northcountry)
Wild plums (Canadian wild)
Rhubarb (it's used as a fruit, so it gets included)
Nanking bush cherries
Hansen's bush cherry
Carmine jewel sour cherry ( the nearby orchard also grows Romeo and Juliet varieties with great success)
Chokecherries (and chokeberries, though I didn't currently have any)
Strawberries (I have Honeoye and Sparkle)
Gooseberry (unknown cultivars, but they are green/white and red)
Currants (red and black but unknown cultivars)
That's all I can think of right now, especially this time of year. Other things I am growing but am unsure of their long-term survival are: autumn olive, pink popcorn blueberries, goji berries, black raspberries, and Siberian stone pine)
Other fruits that are in plans to try are mountain ash varieties Rabina and Shipova, Victory quince, elderberries, mulberries, lingonberry, bilberry, and grapes.