This is a riser for the IKEA Norbo wall table, mine was not plain when open so I designed this riser to keep it almost level; since there is not much clearance the lower part is open to slide it in place.

I designe this 17mm tall since this was my need, but you may scale it down without issues, while you should pay attention to the hole depth of the table if scaling up.

Print with an infill of at least 50% since it will hold a lot of wheight.