Is there a database of Linux compatible hardware?

Centralized, I don't think so.

But maybe this one is something you are looking for:

• Linux Hardware Compatibility Lists & Linux Drivers

There are some other sites:

• Ubuntu Certified hardware
• the sticky posts here: Ubuntu Forums: Hardware
• Debian Hardware Portal

For laptops:

• Linux Laptop Wiki
• Linux on Laptops

And an older list:

• Linux Hardware Compatibility HOWTO

And most likely there are compatibility lists on every major distributions' site/forum, and some specialized sites like for TV-tuners:

• Hardware device information - LinuxTVWiki

A database of Linux-compatible computers & devices: https://linux-hardware.org/

Timeline of tested computers: https://linux-hardware.org/?view=timeline

A tool to analyze and count your computer: https://github.com/linuxhw/hw-probe

I'm the author of this project, so feel free to ask any questions in comments!

Linux Hardware Guide looks like a good resource.