A tool called REcollapse has been developed to assist in blackbox regex fuzzing to bypass validations and discover normalizations in web apps. This tool can be used to bypass restrictions imposed by various types of WAFs. The blogpost on this tool should include details about how it works, its applications in bypassing WAF restrictions, and examples of scenarios where it can be useful in web security testing.
For more details, check out the original tweet here: https://twitter.com/hackwithmax/status/1857556866076663871