A simple list of self hosted alternatives :
File Hosting
- NextCloud : https://github.com/nextcloud
- Seafile : https://github.com/haiwen/seafile
Read-it-later
- Wallabag : https://github.com/wallabag/wallabag
- Shaarly : https://github.com/sebsauvage/Shaarli
Git Repository Manager
- GitLab : https://github.com/gitlabhq/gitlabhq
Wiki
- MediaWiki : https://www.mediawiki.org
Mail Server
- iRedMail : http://www.iredmail.org/
Ticketing
- GestSup : https://gestsup.fr/
Vulnerability scanner :
- OpenVas : https://www.openvas.org/
- Arachni : https://www.arachni-scanner.com/
- indusface : https://www.indusface.com/