One of the most useful things I’ve printed is the 1 2 3 block from here: https://www.thingiverse.com/thing:1793172 and these setup bars. If you want to be serious then you should buy proper setup bars, but these are lightweight, durable and handy. A worthwhile print. Print one of them and check the dimensions, if you need to adjust them, I’ve uploaded the Fusion 360 archive. My Makerbot z18 has a 1/128 of an inch variation along the print. That was good enough for my uses. Watch this video about how to use these together. https://youtu.be/VgpbUzfjDeQ?t=658