Recently I've been using JUnit Pioneer, which is an extension library for JUnit Jupiter (JUnit 5). It contains a lot of useful annotations that are really easy to use in tests, for example to generate a range of numbers for input into a parameterized test. This is a presentation about Pioneer that I gave on March 4, 2021.
In case the embedded slideshow doesn’t work properly here is a link to the slides (opens in a new window/tab).