[kagakuninja]

Come now... Saving rolls use icosahedrons. Old-school paladins used D12 for hit points, I don't know about 5E.

[yetanotherloser]

If your DM had you use these icosahedrons for saves...

https://mymodernmet.com/roman-20-sided-icosahedron-dice/

then you really ARE old-school.