After watching the series all the way through a few times, here are a few of the things I've noticed:
Light Makes Right. There are subliminal messages in this episode (nothing evil, though). There are 2 books that people flip through in this episode- put your VCR on frame-by-frame, if you have it, and read weird poetry, some Gummi Bear stuff, and part of the show's script.
Friar Tum.( I think that's the episode...) At one point in the show, there is a "Dunwyn Donuts" sign in the background.
Beg, Burrow, and Steal. This show has a joke in it that you'll only get if you understand what Zummi says in his spells- he casts a spell, referring to a giant mole, to make it disappear, and a troll's mole disappears instead.
The Sinister Sculptor. There is one scene where the sculptor is placing a rabbit on his shelf, and you can see the sillhouettes of a Mickey Mouse and Donald Duck statue on the sides of the screen
The Fence Sitter. At one point, Grammi holds up a plate of bugs, and the bugs have Mickey Mouse gloves on (this one is unconfirmed).
Bloopers
The Sinister Sculptor. There is a part where Grammi and Gruffi mouth the same line but only Gruffi speaks it.
What You See is Me. Tummi waves to the blind woman, and she waves back