1" table wall mount. Keeps a snug fit against the wall. Other parts (handle and leg holders) in the picture are from other creators I got from Makerworld. 

handles by Meesy and Broom/Mop Holder (scaled up for table legs) by Eneo3d

The longer side is on the top for the table to slide into. I kept the tolerances real close for a snug fit. Once the table is slid into the upper mount you just push your bottom part of the table to wall and ease it into the bottom mount.

I attached a .obj, hopefully that will work for you to adjust for whatever size and thickness board you are using.