Online Tools

ipLeak - Information that all the sites you visit, as well as their advertisers and any embedded widget, can see and collect about you.

httpStatus - Easily check status codes, response headers, and redirect chains.

WebPageTest - Test a website's performance.

PageSpeed / Insights - Analyzes the content of a web page, then generates suggestions to make that page faster.

serpRobot - Free SERP check, track and monitor your search engine keyword ranking quickly and accurately.

DNSsec-analyzer - A good tool that you can use to check DNSSEC. -  Your one source for DNS related tools. - Test for modern Internet Standards like IPv6, DNSSEC, HTTPS, DMARC, STARTTLS and DANE.

CSR_generator - Advanced CSR, Private Key and Certificate triplet generator.

SSLforFree - Free SSL Certificates & Free Wildcard SSL Certificates in Minutes.

HTTP/3 Check - HTTP/3 Check can query given endpoints for support of both IETF QUIC (HTTP/3) and gQUIC protocols.

Is BGP safe yet - Find out if your ISP implements BGP safely