Here is a idea that I came up with the other day, I have seen many threads like this and would like to talk about it for a second.
There are many cheesy or even crazy units in 5th edition but there's still the undeniable fact that they have weakness. So all in all I would like to make a list of units that would qualify as the top units of current 40k.
Here's the list that I will personally pick from, and the final will be decided by vote, please vote.
Space Marine Assault Terminators
Slaanesh Daemon Prince with Lash of Submission
Psyker battle squad
Leman Russ squadrons
Great Unclean one
Vanguards with Storm Shields and Lightning Claw and Jump Packs