You can install third party packages easily in Arch Linux. However, the packages are not pre-compiled, but are known to compile.
The third party packages are organised in the Arch User Repository (AUR) and can be utilised using yaourt. You can find more information about the AUR and yaourt in this question.
One thing to note is that packages in the AUR are usually only for x86_64 or i686 architectures, but you can manually edit the package files during installation and add the arm flag instead, and most build fine.
You can browse the AUR in your web browser here.