These tokens are meant to represent spell slots in D&D. I found that it is much easier for players to remember how many spells they have left if they can hold them in their hand, and it makes life easier for the DM. I may release more tokens in the future for other abilities like the Druid's wild shape or the Barbarian's rage. If you are using a standard .4mm nozzle, I recommend printing these slightly larger.
The pictured tokens were printed with a .2mm nozzle at .1mm layer height. I recommend printing them slightly larger (around 125% scale) if using a standard .4mm nozzle.
If you want, you can fill in the number with a sharpie, or paint to make them easier to read.