LSB-Futures - Identification - Linux Distribution Dependencies
Assumption: By examining packaging dependencies of the major distributions we can quantify what packages are most depended on. These packages might be good candidates for standardization.

Data:

Debian
Using this script gives us a list of source/binary packages and their depends/recommends/suggests counts sorted by number of dependencies. Debian source packages usually map one-to-one with their upstream source package thus giving us a good idea of what projects to target.
Generated from "unstable" US/non-US main/contrib/non-free on 2001-01-25

Annotated version of the source+binary truncated lists.

Mandrake
Sorted list of packages and the number of dependencies on them

Red Hat Linux
This script provides the following output:

Other Distributions
Needed. If you have expertise please volunteer.

maintained by: Matt Taggart <taggart@fc.hp.com>