You're probably thinking "What is Superflex posting this useless thing for?" Well yes, in and of itself it is entirely useless but.can be used to replace screws when designing to hold boards with common 3mm holes. Now there are others like it I know but 3d printed PLA wouldn't be your first pick to make it to the finals if you were building circuit board standoffs. I tried various designs but printability (spellcheck informs me I have just invented a new word) and elasticity of PLA poses some unique challenges. This design attempts to take into account both of these elements and appears to function well for at least one cycle of mounting a board. The standoff when pressed into the hole marginally deform uniformly in the process as opposed to totally relying on elasticity of two narrowly formed sides as others do. This more common method falls painfully short when printed in PLA. Behold the lowly PLA standoff. Less significant than the merits of two vs single ply toilet paper but hopefully also quite useful.

To accommodate for forces in the direction of shear; lateral board movement in parallel to the face of the board, I recommend framing the outer edge of the board in your design. This could be in the form of corners, sides, or a complete perimeter around the edge of the board. If you elect to frame the entire outer perimeter you may want to incorporate a slot or two cut in the frame to allow the insertion of a flat head to pry the board off the stands should you want to remove it in future. The frame could also be slightly returned to interference fit over the top face of the board to assist with shear forces and retention. The combination of snap down standoffs and a perimeter frame should provide a relatively robust mounting solution which eliminates the requirement to use nuts and bolts altogether.

I have linked one of my designs here for a MOSFET mount showing it in a practical application:
https://www.thingiverse.com/thing:2369923