Random number generation made easy. Simulate various types of dice with any number of sides, roll any number of them, get the total as a scalar value and the individual rolls as a list. Optionally generate multiple dice rolls and output them as a list (e.g., generate 6 3d6 for character stats), and a lot more.
ROLL FOR INITIATIVE!

NOT JUST FOR FUN!
Polyhedra also contains simplified actions for getting a random integer (or list of random integers), a random floating point number (or list of random floats), so it's not just for dice simulation.

MAKE GAME BUILDING FAST, FUN AND EASY!
Polyhedra also has 30 built-in numeric states, 30 built-in numeric list states, and a set of 30 "State Triggers" that can be used to ensure synchronous behavior when using the built-in states.

DO A BIT OF MATH!
Additional actions let you set and modify the built-in states in interesting ways (including listwise addition/subtraction) so it's useful anywhere you might need complex numeric states, even if not using the RNG features.

SAVE AND RESTORE!
In 1.0.6 and later, you can even export the value of all of Polyhedra's internal and external states and later restore them via the "Publish States as JSON" and "Restore States from JSON" actions.

Makes it easy to use with Floppy (my browser storage plugin).

"COOL, COOL HOW MUCH DOES IT COST?"

Polyhedra is "Karma-Ware" and while it can be used for free, there is a high likelihood that you will fail all saving throws versus death unless you contribute to the creation of Bubble plugins that don't suck at:

https://grupz.com/karma