Aldo taking down Hominick. Did not expect that. 
shogun got a takedown on mark coleman
shamrock taking himself down against franklin.
ranier wolfcastle -
shogun got a takedown on mark coleman
And Chael iirc (en route to getting guillotined).
Captain Epic - For me it is every time Jose Aldo gets one, for a guy whose spent his whole career being a "striker" fighting wrestlers he's got a sneaky grappling game. I think it was Ricardo lamas he took down a few times and really shocked me. No one mentions it, but I think it may be a larger part of his game plan against Conner than going toe to toe.
They are usually suprising because they come later in the fight (Hominick, Lamas) but he did resort to that game against TKZ when his broken foot started taking a toll. He absolutely has explosive tds though and times them very well too.
keiths - Bustamante Lindland was a huge wtf at the time.
GSP Kosheck of course. We knew there was a chance but he dominated.
BJ Fitch
He got Lindland down twice. 1 of them was off a caught knee, the other was a legit td. Busta also took down Hendo and Rampage. He really was one of the most complete guys of that era.
Anytime anyone with crazy creds gets taken down ...
Brunson taking down Romero twice in a minute was pretty crazy, even though Romero did what great wrestlers do and gave his back, fought the hands and stood up.
Also DC throwing Barnett like that was shocking , I thought Barnett wouldn't beat at mma wrestling and was totally wrong. When DC hits that high crotch it's a show
Randy vs Sylvia was good. It looked like big Timmay was just too big, but Randy kept managing to finish his shots, despite the size and weight disparity.
Brock taking him self down into multiple barrel rolls.