・Mailer
Thunderbird
https://www.thunderbird.net/

・Messenger Software
Signal
https://signal.org/
Element
https://element.io/
Telegram
https://telegram.org/
Discord
https://discord.com/
Skype
https://www.skype.com/

・Collaboration Platform Software
Microsoft Teams
https://www.microsoft.com/en-us/microsoft-teams/group-chat-software
Zoom
https://zoom.us/

・Live video software & Virtual Webcam

・Network　Software
Wireshark
https://www.wireshark.org/
TCP Monitor Plus
https://dns-plus.net/#tcpmon

・Archiver & Extractor Software
WinRAR
https://www.rarlab.com/
7-Zip
https://www.7-zip.org/
Universal Extractor 2
https://github.com/Bioruebe/UniExtract2/releases
caldix
http://www.kmonos.net/lib/caldix.ja.html