List of free test stuff for developerππ½
If you're looking for all programming tools around test (not just free). Check this page List of test Programming Tools

HTTPdump
Debug or inspect webhook and APIβs with httpdump. Create individual endpoints to test, debug or inspect your HTTP requests and Webhooks.
Tag: test, api

Rainforest QA
Rainforest's QA platform combines no-code test automation and professional QA to help you release quality software.
Tag: test, QA
5 hours free per month, No code automate testing