Network

• Interactsh (CLI) | (web) - Detecting out-of-band interactions (DNS, TLS, HTTP and much more)
• webhook.site - Generates unique URLs, e-mail, DNS.

VPN

• Gluetun - Lightweight swiss-army-knife-like VPN client to multiple VPN service providers.
• SSHuttle - VPN over SSH.

Tor / I2P

• i2pd - I2P Deamon.
• NIPE - CLI tool to make Tor your default gateway.

Sniffing / Spoofing

• SSLsplit - Transparent SSL/TLS interception.
• TCPreplay - Pcap editing and replay tools.
• Ettercap - MITM attack.