Lucky enough to play RPGs somewhere with a whiteboard? Want pieces to move without having to buy magnets in a appropriate of colors and sizes?

The RPG magnet is your answer. It can be used on both a magnetic surface and on a board, as the height of the stem makes the 'head' the appropriate height for a normal figure.

Get som 4x4x4 mm magnets (the strong kind) and print the RPG magnet in the colors you want!
It may also fit round magnets, up to 10 mm diameter, as long as they are not too thick for the stem to be screwed on securely and that the magnet can hold up about 7 grams while penetrating 0,75 mm plastic.

The basic is a base and stem. Put the magnet in the stem and screw it on the base; if it rattles, when you shake it, tighten it further!

The default print also come with two caps. The cap fits on top of the stem and makes it easy to change the 'identity' of a piece as well as which way it is facing.
Put a dymo-label with character names on the caps you usually use to make it easy to identify the pieces by both color and name.

Need to identify different monsters? Make some extra caps and use the 'dice stensil' to draw dice numbers on them.

Updated version avaliable

With our experience of using these, I have made an updated version here: https://www.thingiverse.com/thing:3002335