Troll

For the longest time there was only Cave Troll of Moria, Scourge of the Black Pit, his hammer and his chain.

Then Ents of Fangorn released and Sauron culture got Gate Troll and Troll of Udun. The pair even came with their own toy.

Trolls blasted onto the scene in Siege of Gondor (Great Hill Troll, Olog-hai of Mordor and Troll of Gorgoroth, Abomination of Sauron) and it got worse from there.