LAN Messenger - LAN Messenger is a decentralized UDP IM-style chat client which supports usernames...
Bashupload - Upload files from command line to share between servers
Feem - Share files offline. No servers. No cloud. No limits.
BlackHole File Transfer - Blockchain-based file transfer. Designed for everyday use.
BeeBEEP - You can message and share files inside your intranet without a server.
FilePizza - Open source application used to transfer file via WebRTC and WebTorrent.