Some examples of deprecated methods, as detected by phpstorm:
assertInternalType()
assertAttributeEquals()

Changelog for 7.5 which mentions the deprecation here (under 7.5.0 heading): [https://github.com/sebastianbergmann/phpunit/blob/7.5/ChangeLog-7.5.md

Looks like these will be dropped for 9.0 (https://github.com/sebastianbergmann/phpunit/issues/3370)