I have seen this, where to find

[Bert Blaine]

looking for an extension that lets you change critical damage to max 1st die and roll a second. anyone know where i can find one.

[Trenloe]

Ruleset?

[Klandare]

looking for an extension that lets you change critical damage to max 1st die and roll a second. anyone know where i can find one.

This works for multiple rulesets but I use for 5E (so know it works well there):

Improved Critical (https://forge.fantasygrounds.com/shop/items/115/view)