This is just a list of tools I’ve been using recently, which I can refer back to quickly, without having to look for them again in my bookmarks.
ATLAS – https://atlas.mitre.org/
Crack Station (for cracking hashes when the wordlist doesn’t work) – https://crackstation.net/
Cyber Analytics Repository (CAR) – https://car.mitre.org/
Domain Tools Whois lookup (for finding IP and ASN information) – https://whois.domaintools.com/
Hashcat Example hashes (for identifying hash types) – https://hashcat.net/wiki/doku.php?id=example_hashes
Hashes.com (online hash identifier) – https://hashes.com/en/decrypt/hash
Leaked passwords/credentials (wordlists) – https://github.com/danielmiessler/SecLists/tree/master/Passwords/Leaked-Databases
MITRE AADAPT – https://aadapt.mitre.org/
MITRE ATT&CK – https://attack.mitre.org/
MITRE Adversary Emulation Library – https://ctid.mitre.org/resources/adversary-emulation-library/
MITRE D3FEND – https://d3fend.mitre.org/
MX Toolbox – https://mxtoolbox.com/
PhishTank – https://phishtank.com/
Spamhaus – https://www.spamhaus.org/