Nice collection, thanks.
Dunno whether the point is to add to the useful tools or not, but here's one (not a tool per se, so can't add it to the git repo). Since I'm new to the community, don't know to what extent this is popular around here, but I haven't found any other tool to create BGA footprints (it also supports QFN, QFP, edge connectors, but since high pin count BGAs are nightmare to create by hand, this is what I appreciate the page most for). The only issue I've found so far is, that even if you set to create the footprints in mm instead of mils, the end result is in mils regardless and is 2.54x bigger than expected, so just save your time and convert the dimensions to mils straight from the beginning. So far I've used this for DDR ICs, eMMCs, SoC's and Eth Switch ICs and it works great. However if you wonna use BGAs with different pin sizes and pitch inside the package (like the intel Atoms, where the mid section of pins is with lower pitch and smaller diameter), then this might not work straight out of the box for you (still haven't figured out how to automate this).
Rohrbacher's page - I'm not affiliated with the page, nor with its creator in any way - just find it really useful and think someone else would appreciate it.
P.S. You should also know, that once you create the footprint, you would need to import the module, create a new pretty lib from it and then you'd be able to mod it (KiCAD 4.x doesn't seem to like legacy modules for editing and doesn't let you to).