ATMs I’ve checked:

BNP Paribas: no balance inquiry option. Nor did it print the balance on the receipt.

Attijariwafa: no balance inquiry option. Anti-feature: you must enter your PIN before it shows you the menu. Does that mean it connects to my bank even in the absense of a transaction?

Ing: no longer has ATMs?
KBC: no longer has ATMs?
Belfius: no longer has ATMs?
Aion: only has 1 ATM (unplugged, grafitti on screen)
Europabank: no longer has ATMs?
DHB bank: has no ATMs?
Fintra: ATM is the same as BNP Parabas?

Batopin: no balance inquiry option. (this is a 3rd party hired by Ing & KBC)

This website claims to give a way to check your balance, but I’m not so trusting:

https://www.getmybalance.com/