In big tabletop games, it's hard to keep track of what dice are tracking what, and to remember what the dice were before someone knocked the table or had to move their setup.  In particular, with a big Commander game, I can't tell how many times we'd accidentally grab a D10 to track counters and later realize it was supposed to be for someone's life total.  I made this model to try to hold the dice stable and keep them separated from the other dice to minimize mixup opportunities.

NOTE: D10s and D%s do not have a standardized shape/size!  This model works for the Chessex dice, and may work for others, but that hasn't been tested!  Feel free to modify the attached SLDPRT (2024 EDU) file to test different manufacturers.