Mx ToolBox - https://mxtoolbox.com/blacklists.aspx
BPG Hurrican electric - https://bgp.he.net/
Qualys SSL test - https://www.ssllabs.com/ssltest/
Cloudflare URL Scanner - https://radar.cloudflare.com/scan
Gordon - https://cybergordon.com/
PulseDive - https://pulsedive.com/
Whois search - https://whois.domaintools.com/
VirusToal - https://www.virustotal.com/gui/home/search
URLScan - https://urlscan.io/
DNS Dumpster - https://dnsdumpster.com
Wappalyzer - https://www.wappalyzer.com
Builtwith - https://builtwith.com/
Exploit-DB - https://www.exploit-db.com
Certificate Stream - https://crt.sh/
FOCA - https://github.com/ElevenPaths/FOCA Required - MS-SQL Server 2017 Express
NMAP/Zenmap - https://nmap.org/zenmap/
OpenVAS - https://www.openvas.org/