Small collection of links to different projects/tools/teams/etc.:

Read me first

PC Hardware / Laptops

DNS2IP converters

Embedded hardware

Smartphone

Firmware

Security focused Desktop OS

General purpose OS

Smartphone OS

Router OS

Encryption software for general purpose

For block devices:

Proprietary drivers free alternatives

Web browsers

3D printer

Office software

Instant messaging clients

Jabber(XMMP) support

Graphical editors

Vector editors

UML Schematics

Typesetting

LaTeX / TeX

3D editor

Automated server configuration/provision

Nice online tools

TLS