Upstream Bug Resources
The Upstream Report - Bug linkage percentages for the top 50 projects in Ubuntu, sorted by open bugs. Please note that this report is still in Beta. Instructions for using the report.
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!)