Here are some random ones off the top of my head. I'm happy to accept that you can't think of any value of these to bad guys, but the bad guys are not limited by your or my imagination.

MongoDB and all the drivers https://github.com/mongodb

Mixpanel analytics libraries https://github.com/mixpanel

Sencha Javascript libraries https://github.com/senchalabs

Yahoo YUI and various other JS related gunk https://github.com/yahoo

Shopify ecommerce libraries https://github.com/Shopify

Engine Yard tools & utils https://github.com/engineyard