Gaylussacia brachycera (box huckleberry) is one I went with that is evergreen and stays below 2 feet tall. Lowbush blueberries and lingonberry should work too.
Check Hartmannsplantcompany.com for all 3. They also have bearberry but I’m not familiar with that one.
I am gonna put some strawberries in between mine. Everbearing so should have 2 crops. Will probably put some black rasps in as well if my spacing works out. Maybe a few haskaps as well.
How about some of the more dwarfish gooseberries, like Hinnomaki Red and Yellow? Hinno. Yellow is downright minuscule: mine can’t even break the 1’ barrier. Would be a good one to squeeze in among other plantings.
i have alpine strawberries, arctic raspberries, mid height blueberries, lowbush blueberries, lingonberries, Jeanne gooseberry, red currant, rhubarb and dewberry. all are less than 2 ft. and grow well in front of or in between my trees.