Excellent question, I should have been more accurate in my use of such a value driven word like "good". I don't necessarily mean in a qualitative sense as we would understand it, I doubt we would enjoy satire plays more than we do the Medea. I mean in terms of reconstituting classical Athenian culture.
So "good" in terms of what the Athenians themselves voted for, as far as we can tell, or otherwise exerted a significant influence over the development of the genre. The prime example would be Aeschylus' Achilleis trilogy. For Aristophanes' it was the crown jewel in the dramatic crown, it scored first place in its day and was most likely responsible for some of the most important innovations of tragedy: It managed to actually stage the Ilias (more or less); added the second hypokrites, made use of offstaging for the unstageable; making use of the trilology format ktl. Essentially those three would have been amazing to have and would alter our perception of the genre. We only have indirect testimony.
Likewise Phrynicus' play on Miletus was one of extreme literary and historical importance, but then that was always doomed to failure.
I use Medea as a pertinent counter example, it took third prize and was comparatively unimportant in its time, though considerably popular afterwards. Likewise Sophokles' Oedip. Rex. took second prize but enjoyed a good afterlife as a Byzantine school text.
Now that's not to say we don't have lots of first prize winners, we do, or that the prize is the only indication of of worth (it's not). However, the genre is not in as good a condition as one is lead to believe by the handbooks. Its not AS bad as philosophy in which case Christians and Arabs have had too big an effect on our corpus. But still, too often the surviving texts are treated in an over privileged manner for the time period. I don't mean to come down too hard on tragedy and hope it doesn't come across as that.
EDIT: BTW here are the Radt numbers for possible fragments of the trilogy I mentioned: Myrmidons 131-142 Radt; Nereids 150-4; Phrygians 263-72. They're probably online somewhere or in a Loeb, you can check the comparative numeration in the back.
Will not answer questions which only need a basic knowledge of grammar. Pay attention to the textbook.