One thing that is often needed is some sort of counter, for counting things like hit points, levels, or objectives achieved. From various files on Thingiverse, with some modifications on TinkerCAD, I assembled the dials shown in the photo below. There are little 5 mm x 1 mm neodymium magnets in the top and the bottom, which hold the two parts together while allowing the dial to be turned to show the number. I had a lot of difficulties with other designs, because my 3D printer can only print one color at a time, and that made numbers hard to read. In this design the numbers stick out from the background, and I could easily paint them.The other items shown on the photo are for Gloomhaven. After spending a lot of time punching out cardboard tiles for doors, bookshelves, and other pieces of dungeon decoration, I decided that they would look a lot better in 3D. Search Thingiverse for Gloomhaven, and you will find a 3D version of every cardboard tile in the game. I especially liked the design for the doors, in which the base fits the Gloomhaven hex, and the top is removable for when the door has been opened. But I am just printing the dungeon decoration. There is a whole system on Thingiverse for you to print the map tiles as well, but I didn't feel the need for that.

For both Gloomhaven and Too Many Bones I 3D printed custom design boxes for holding cards. In the Too Many Bones case the idea was to have a box hiding the encounter deck, so that you could draw a card without seeing it first (they are printed on both sides). For Gloomhaven the big square cards with the monster stats had no place in my insert, and I wanted a box to keep them together. That sort of item is easily designed in TinkerCAD, as it is just a hollow cuboid with one open side.

All this doesn't change my evaluation of home 3D printing as a solution in search of a problem. Unless you have a good application in which 3D printed parts are useful, a 3D printer is of not much use.