You have to be specific.
If you suggest PRNGs (Pseudo Random Number Generators) be assured that you will deal with something that is not industry standard and then you have lost the point with your tetsts as what they produce will not reflect what is industry standard. PRNGs use algorithms that use mathematical formulas, or simply precalculated tables, to produce sequences of numbers that appear random but can give you some nasty surprises.
True Number Random Generators (TRNGs), use often a physical phenomenon like a radioactive source to connect it to a computer The points in time at which a radioactive source decays are completely unpredictable, and they can be detected and fed into a computer, avoiding any buffering mechanisms in the operating system.
The Lavarand Generator is also something worth studying https://en.wikipedia.org/wiki/Lavarand [nofollow]
In the end, my advice to you is to use an industry standard RNG that applies TRNG principle. Hence you are able to implement your tests into something "real" andavailable in many casinos world wide.
But if you stillpersist to make your own custom made settings you can always use this simple tool: https://www.randomizer.org/ [nofollow]