SWI-Prolog -- library(random)

getrand/1	Query/set the state of the random generator.
maybe/0	Succeed/fail with equal probability (variant of maybe/1).
maybe/1	Succeed with probability P, fail with probability 1-P.
maybe/2	Succeed with probability K/N (variant of maybe/1).
random/1	Binds R to a new random float in the _open_ interval (0.0,1.0).
random/3	Generate a random integer or float in a range.
random_between/3	Binds R to a random integer in [L,U] (i.e., including both L and U).
random_member/2	X is a random member of List.
random_numlist/4	Unify List with an ascending list of integers between L and U (inclusive).
random_perm2/4	Does X=A,Y=B or X=B,Y=A with equal probability.
random_permutation/2	Permutation is a random permutation of List.
random_select/3	Randomly select or insert an element.
random_subseq/3	Selects a random subsequence Subseq of List, with Complement containing all elements of List that were not selected.
randseq/3	S is a list of K unique random integers in the range 1..N.
randset/3	S is a sorted list of K unique random integers in the range 1..N.
setrand/1	Query/set the state of the random generator.