3DPrint D4 Numeric
Dice seem like a good first thing to 3D print, small/fast and they do have an actual use. So this was one of the first things I experimented with.
The indent of the glyphs may seem a little deep (some of the numbers almost intersect) but it really is necessary for useable legibility. For extra legibility you could try and fill in the glyphs with another material after printing.
The blend file is setup to use instanced text objects to cut the letters into the main object. Which means you could adjust the font/size/etc if you know how to blender. If you do not know how to blender then you want the STL file and will need to slice it yourself.
I have an Ender 3 Pro loaded with PLA and I use https://slic3r.org/ with a layer height of 0.25mm which seems a good compromise between speed and quality for a 0.4mm nozzle.
From various test prints I discovered that you can actually get away here with a 0% infill but a 100% infill seems best as it gives the die a little bit of heft and helps to keep the weight balanced.
I recommend not bothering with support or a raft just be extra careful with bed calibration as it is very easy to squash the bottom layer into the print bed rendering its numbers illegible.