Upstream Bug Resources
Bugs that need forwarding to the Upstream bugtrackers.
Unlinked upstream bugs - Sometimes people add a link to an upstream bug tracker in the comments of a bug but don't bother creating an upstream task. This is a list of possible targets that can be linked. (Lots of low hanging fruit in this list, but also a bunch of dupes and ones inappropriate to be linked.)
Why Upstream? - Thoughts from freedesktop.org on why sending things upstream is a good idea.
There are also some cases where you don't need to file a bug upstream, for those cases please have a look at When not to Forward a bug upstream
Upstream bug trackers
Instructions for how to file bugs in specific upstream bug trackers. (Feel free to add more!)