as far as i know (not the furthest) there isnt any solid math saying non-platonic solids are unequal. i think i wrote that confusingly, non-platonic solids used as die seem to be fair.

... Dungeon Crawler Carl?

If you use 3D8 in placed of 1D20 and add 3 to all DCs you get system with a reliable bell curve for skill checks.

GURPS uses 3d6 for this exact reason.

"Nowadays they're letting just anything be dice! Pentagonal trapezohedron? Next you're going to tell me a zocchihedron or Catalan solids are going to be allowed in my game!"

Dungeon Crawl Classics. Definitely worth checking out. It's a TTRPG by Goodman Games and it's actually a lot of fun. Two gimmicks that the game is known for is using oddly shaped dice (d5, d7, d30) and the funnel. A level 0 adventure where characters who survive become level 1 characters.

A part of the charm in Dungeon Crawl Classics is the swingy randomness.

I've never heard of Daggerheart. I'll have to check it out! Especially because d12s get no love in 5e.

11 definitely gets closer to 11 than 12 does.

It's basically the official Critical Role original system. Its licensing isn't as great as Paizo's, from what I hear, but it looks like a pretty great system mechanically from what little I know of it.

For some, but not me and my fellow GURPS brethren

I bought one of these a few months ago. It's fun, but not [isohedral](https://en.wikipedia.org/wiki/Isohedral_figure).

Any convex [isohedral](https://en.wikipedia.org/wiki/Isohedral_figure) polyhedron is a fair die by symmetry. Non-isohedral dice *can* be made fair, but only through emperical testing, not symmetry.