In probability theory and statistics, the beta prime distribution (also known as inverted beta distribution or beta distribution of the second kindJohnson et al, p 248) is an absolutely continuous probability distribution.

In probability theory, a beta negative binomial distribution is the probability distribution of a discrete random variable  equal to the number of failures needed to get successes in a sequence of independent Bernoulli trials.

In probability and statistics, the generalized beta distributionMcDonald, James B. & Xu, Yexiao J. "A generalization of the beta distribution with applications," Journal of Econometrics, 66(1–2), 133–152 is a continuous probability distribution with four shape parameters, including more than thirty named distributions as limiting or special cases.