The third one looks like a LFSR [0]. I didn't recognize it at first because the factors used here are not the common ones that produce well known periods; not s

The third one looks like a LFSR [0]. I didn't recognize it at first because the factors used here are not the common ones that produce well known periods; not sure what period this one would have. For what it's worth, LFSRs can be nice for generating random sequences with periods of predictable length - and they're cheap! They also recently got a bit of a publicity bump with the rediscovery of how Doom used one for the "death fade" transition, that randomly but exhaustively overpainted all screen pixels with blood red. [2] [0] https://en.m.wikipedia.org/wiki/Linear-feedback_shift_register https://en.m.wikipedia.org/wiki/Linear-feedback_shift_regist... [1] http://fabiensanglard.net/fizzlefade/index.php http://fabiensanglard.net/fizzlefade/index.php But in general - yeah, there's a lot to consider with picking RNGs, not the least of which being context. For games Xorshift is often a good enough choice because it's fast, small, and the game environment is chaotic already (because of the unpredictable players) so there is rarely need for something much stronger.