Out of band Security Testing

Always interested in finding new ways to test blind injection and out of band responses. Here are some of the free and opensource tools i use apart from the paid burp suite collaborator:

1. http://pingb.in
2. https://webhook.site
3. https://xsshunter.com
4. https://transfer.bi.tk
5. https://www.canarytokens.org
6. https://github.com/JuxhinDB/OOB-Server
7. https://github.com/projectdiscovery/i... (github) https://app.interactsh.com (web client)

what do you use? are there any better free/paid tools for out of band testing?