I made a web page where you can simulate a complex dice roll sequence with conditionals (e.g. re-roll when roll is a 1) using a Python-like syntax. (Click the "Toggle Syntax" button to view examples)
It needs a second to load because it has to load a Python interpreter in the background (I'm not good at web development) but once that's done, it works really well.
It's still very barebones and I still have to work out some problems.
Maybe some of you could use it, though.
There's also just the Python version available to run locally here
Everything is GPLv3, enjoy!
Thank you very much. I, too, initially used a sampling approach but that was obviously inefficient and inaccurate. Getting this to work was a HUGE pain so it's nice to read some kind words about it, thank you