This is Kali Linux's ISO images repository: https://cdimage.kali.org/

Kali Linux is an open source security auditing and penetration testing Linux
distribution: https://www.kali.org

Download Kali Linux ONLY from official mirrors!
https://docs.kali.org/downoading/download-official-kali-linux-images

Grab the latest images from the "current" directory. If you need
older images, you can find them on http://old.kali.org/kali-images/

Kali Linux is a project by Offensive Security - https://www.offensive-security.com