Tools

Crypto

Vigenère cipher solver - https://f00l.de/hacking/vigenere.php

Frequency Analysis - https://f00l.de/hacking/freq_analysis.php

Wordlist Generator - https://f00l.de/hacking/wordlist_generator.php

MD5 decrpyt - https://www.md5online.org/md5-decrypt.html

Network

PCAP file fixer - https://f00l.de/hacking/pcapfix.php

Steganography

File Type Revealer (online binwalk) - https://f00l.de/hacking/reveal.php

Exploit

embed code from a binary for usage in a c-program or perl-script - https://f00l.de/hacking/bin2code.php

pwntools for writing Python scripts:

pwntools: python3 -m pip install --upgrade git+https://github.com/Gallopsled/pwntools.git@dev3