Name:RetroShare (Free)
URL:https://retroshare.cc/
Utility:This free tool – 

• Helps establish encrypted connections 
• Chat service – To send text and image, also has rich smiley set  
• Mail service – Send encrypted messages to other members of the network 
• File sharing – With accelerated transfers and ability to share large files 
• Forums – Read and write forum posts offline 
• Links sharing
• Channels – To publish and download the files, comment on them  

Special Features:

• Free and open source
• Cross platform
• No ads, no term of service 
• Can be used over I2P or TOR networks