Pseudorandom number generators, of course. Which are deterministic algorithms for generating pseudorandom numbers from a seed.

But I mean, specifically, using CSPRNG (such as an algorithm behind /dev/urandom) vs pseudorandom number generators such as rand() from C library.

You can read more about them on Wikipedia:

https://en.wikipedia.org/wiki/Pseudorandom_number_generator

https://en.wikipedia.org/wiki/CSPRNG