If we're talking about raw power and sheer intimidation factor, Azog the Defiler has to be at the top of the list. That pale orc from 'The Hobbit' films wasn't just some mindless brute—he was a strategist, leading armies and even going toe-to-toe with Thorin Oakenshield. The way he wielded that spiked mace-arm was terrifying, and his presence on the battlefield shifted entire conflicts. Then there's Bolg, his son, who inherited that viciousness and took it further with even more brutal tactics during the Battle of the Five Armies.
But let's not forget the OG orcs from the original trilogy—Lurtz, the Uruk-hai captain who took down Boromir in 'The Fellowship of the Ring'. That guy was a monster, shrugging off arrows like they were nothing. And Gothmog, the deformed lieutenant in 'Return of the King', who commanded the siege of Minas Tirith with a mix of cruelty and tactical cunning. It's hard to pick a single 'strongest,' but these are the ones that left the biggest impact on me.