List of of tools I have found to be useful conducting cybersecurity CTF training:

CyberChef

Md5 Decrypt & Encrypt

EXIF Data Viewer

Canarytokens

URL and website scanner – urlscan.io

Grabify IP Logger & URL Shortener

Shodan Search Engine

OSINT Framework

SpiderFoot HX

Google Hacking Database (GHDB) – Google Dorks, OSINT, Recon

StegOnline

If you are still not satisfied, check out these lists of web-based and desktop-based security tools:

Online Tools to crack CTF Contests

Pentesting tools | theyknow

List of Awesome Red Teaming Resource

Rawsec’s CyberSecurity InventoryTop TOOLS for Web Application CTF