Guesstimate (https://getguesstimate.com) has been around for years. I assumed Excel and Google would incorporate its features quickly, but it never seems to have taken off.

Features:

- All cells are named (auto named if you don't set them)

- Cells can have single values, many types of probability distribution, or sample data

- Formulas also produce distributions as first class outputs, because calculation is a Monte Carlo sim

- Each cell also has a pop-up box that invites you to explain your reasoning -- built in documentation

It got so much right. Sample data particularly useful because you can build a probabilistic bottom-up forecast and then update it with real-world data.

Wow, this is incredibly cool. I can't believe this stuff hasn't been ported into Excel.