the probability plot assesses whether or not a data set follows a given distribution.

if you have two samples, and know a prior that they follow some specific distribution, you then can use probability plot.

Bihistogram plot can also be informative.

For purely investigate whether the two samples have the same distribution(whatever this may be), use Q-Q plot(quantile-quantile plot).

Kolmogorov -Smirnov Goodness of fit test (K-S test) is a quantitative test whereas the above mentioned are visual checks. K-S test is used to decide whether a sample comes from a population of specific distribution.

alternatives of K-S test are Anderson-Darling test and Chi-squared Goodness-of-fit test.