This is a set of all 66 octiamonds, a well known puzzle concept consisting of all different pieces which you can create from eight equilateral triangles if you glue them edge to edge in the plane. There is a piece number engraved on one side of the piece using Michael Dowle's numbering system, cf. footnote. Octiamonds are of course not invented by me. Search engines lead you quickly to sites describing the puzzle concept. I print them in 11 different colors grouping the following pieces together:
(21,24,32,37,60,66) (7,14,46,49,51,58) (1,30,31,42,52,55) (6,19,35,43,47,64) (2,33,36,39,48,59) (10,20,22,26,53,65) (18,29,50,54,61,62) (5,12,13,38,56,57) (16,25,27,28,34,40) (9,11,15,23,44,45) (3,4,8,17,41,63)Each set of pieces of one color can be combined to the same geometrical shape (a discovery of Patrick Hamlyn, cf. footnote) such that you can stack them in 11 levels. I have also designed a box which uses this format. The orientation of the engraved number is chosen such that the number is face up when putting the pieces into the box. This together with the colors makes it comparatively easy to get the pieces back to the box.
You could also print all pieces in two colors (half the layers in one color each) and so allow for a second colour scheme allowing for a second way of stacking (e.g. 6 layers of 11 pieces, cf. the last photo); in most cases the orientation (engraved piece number face up) would then however work only for the first color scheme described above.
I have printed the pieces and the box both in PLA and PETG. For the box cover PLA might be superior due to better bridging.
footnnote: facts about octiamonds quoted from mathpuzzle.com/octiamonds (downloaded 13th March 2021).