In terms of sponge, we have very few exclusive plugins to make our systems work. Additionally, I release a lot of my plugins in some way, sometimes just on my github. ClearMob is the plugin I started into Sponge with, and it is publicly available here on the forums, (Its a ClearLagg port)
Besides that, we use Pex, and Griefprevention, which are both freely available here. Nucleus as well.