I think the "art dumps" you are referring to are collection of sketches. Individual pieces that aren't just variations of each other should be treated as individual submissions.
As for the quality: Simply share what you think looks good.
For reference, this is your current competition:
https://www.newgrounds.com/art/browse?interval=month&sort=date&genre=0&artist-type=undiscovered
SouSTAR
Wut?
Just... Post whatever you want as long as you don't break any rules? It's really that simple :)