The dragon egg currently can only be gotten on the FIRST kill of the Ender Dragon. Would it be possible for you to allow it to be obtained on subsequent kills (in case it was destroyed, etc.)?

https://github.com/Vazkii/Quark/blob/master/contributing.md

Suggestions are not accepted here. Since quark is a mod for features that will go in vanilla, post your suggestions to /r/minecraftsuggestions and tag me (/u/vazkii) if you want me to see it. I take notes of all features I intend on adding.

Done. Though, this isn't really new content so much as a tweak that really should be there in vanilla.