I printes all letters of the alphabet in lower and upper case for my wife. She is a teacher at the elementary school and she will use these letters for her lessons.
The font is Arial but I added some characters from other fonts, you can find them in the zop-file as additional file, e.g. a2a.stl (lowercase a). I did so to use more simple glyphs.
I added the uppercase letters A,B,C for your preview. You can find all letters in the zip-files, for uppercase and lowercase an own file. The letters are design to have a height for uppercase of 10cm and a thinkness of 1cm. Please feel free to resize.