I've got two for today.
The chainsaw-hand comes the "Alien Commander" from the Battleship Kreons, which have a lot of interesting parts I hope get carried over to the TF line. "Combat Diver"
could easily be straight repainted as Sea Spray.
Grimlock in glorious G2 (he, along with Slag and Snarl, were the first TFs I recall owning)
I think a pair of Optimus' smokestacks on Dirge's wing-support-doohickey does a fine enough job evoking Grim's teeny Tyrannosaurus arms, if in an abstract implied way.