Though it depends on which one you watch, since with how popular abridging has become, there are bound to be a few different groups abridging the same thing
Seeing that LittleKuriboh voices Freeza ... at the end of Episode 24, he says "... give me some ideas." He sounds a lot like Florence (a.k.a. Yami Bakura). Interestingly enough, one of his quotes is said earlier in that same episode by Krilin. When he transforms, he sound a lot like Yami Yugi, especially when he says "All done."
Freeza also tends to sound like Marik Ishtar whenever he gets angry, especially when he shouts "I WILL F***ING MURDER YOU!" to Nail.
From the Bardock: Father of Goku special and onwards, many of the sound effects come from the Orange Box. In particular, all grunts and yells of mooks during combat are clearly those of the characters from Team Fortress 2. May also count as a Shout-Out.
Bill Murray also filled in as Yamcha between Vegeta3986 and Faulerro.
In the Bardock special, one of the scientists looking over Goku's pod is Christopher Sabat.
Masako X, Takahata101, and Lanipator all lend their voices to episodes of Death Battle, with Masako X and Lanpinator reprising their roles as Goku and Vegeta respectively.
I Knew It: After Freeza's comment on how Guru can be so fat when Namekians only live on water lead many to believe that Guru caused the great drought by simply drinking it all. They were right.
That the Garlic Jr. Saga would be covered in only one episode.
Insistent Terminology: KaiserNeko is a Troper, and often visits this very page. One of his common quirks is editing instances where other Tropers mistakenly spell Freeza's name as "Frieza". While the official English release usually cites the name with the I-E spelling, in DBZ Abridged, the E-E version is used.
Although, Son Goku has consistently referred to him as "Freezer" in-universe. That's the joke.
Episode 33 parodies this by having Trunks pronounce it as "Fry-za", which is then corrected by Freeza and his father—a bit of Fridge Brilliance when you realize who voices Trunks.
Magnum Opus: For all the abridged writers who contributed.