A frog magnet remixed from https://www.thingiverse.com/thing:3226514
All files use two 6x2mm magnets.
The small-thin variant is intended to eliminate a couple of superfluous layers. The magnet fits into the cheek area so it may be possible to thin it a little further.
Some care should be taken to try to get the best surface quality, which can be tricky with mismatched coloured filament. Surface ironing will help.
The 3mf file is pre-coloured using black as the base.
The author hasn't provided the model origin yet.