[sfvisser]

Another great approach to generating notional data is using the Haskell QuickCheck library and specifically the Arbitrary type class. Super simple and extremely flexible/composable.

Probably also available in other languages.

[aldanor]

The ones I used and can recommend:

“hypothesis” package in Python (+pytest plugin)

“rapidcheck” in C++

“quickcheck” in Rust

[LrnByTeach]

good list for generating model data / fake data

[portlander12345]

testcheck is a JavaScript equivalent.