Olivera's calf slicer is still (afaik) the only compression sub in UFC history and the look of agony on Wisely's face really puts it in the elite tier along with KZ's twister and some others.
All these pages and no one has included the real answer.
The real answer is the same as the best submission in competitive jiu-jitsu history--the same submission that was so good it got BANNED.
Korean Zombie's Twister
I also always like BJ Penn's RNC on Matt Hughes. That was glorious.
It was mentioned in the OP and multiple times on the first page.