Bisping v Rockhold was absolutely legendary, think that one can't be mentioned enough. Usman vs Colby another incredibly satisfying finish.
GSP finishing Hughes and winning the welterweight strap for the first time was also awesome, especially with how much shit Hughes talked about GSP tapping quickly the first time and trying to insinuate that he had no heart. And then of course GSP ended up armbarring him back in their rubber match.
One that likely won't get mentioned by others but I personally found enjoyable was Wonderboy finishing Hendricks, as that pretty much killed his hype train. I never really liked Hendricks and found him to be really arrogant, and he often coasted in the latter parts of fights and eventually lacked the discipline and professionalism to make weight properly as well. In his juiced up prime he was quite the formidable fighter but it really did seem like once USADA put in stricter rules he fell off hard without the juice and IV weight cutting. By the end I did feel sorry for him a little, as he clearly couldn't handle middleweight and was eventually used as prey for Paulo Costa. Also, after all the shit he talked about GSP after their fight, him getting his MMA career finished to open a card that GSP headlined and won the middleweight belt in while Hendricks was getting drowned in that division made it a very poetic ending for me. Then getting knocked out in bare knuckle boxing was just the cherry on top to completely end his combat sports career.
If Jon Jones ever gets KOd, you'll definitely see that on my list.