クラウドストレージ
OSS (Open Source Software)
参考：
5 open source alternatives to Dropbox | Opensource.com
3 Self-Hosted Dropbox Alternatives, Tested | MakeUseOf
Open Source Dropbox Alternatives | AlternativeTo.net
Self-Hosted Dropbox Alternatives | AlternativeTo.net
The 8 Top Free and Open Source Dropbox Alternatives | Capterra Blog
The 9 Best Free Dropbox Alternatives for Linux | FOSSMint
Are there any free and open source Dropbox alternatives that actually behave like Dropbox? | Quora
ownCloud
参考：
ownCloud – The leading OpenSource Cloud Collaboration Platform
Nextcloud
参考：