Board Thread:Lore/@comment-67.10.139.249-20150623235701/@comment-25101089-20150624004338

And as for the types of Trolls:


 * Stone Trolls (the ones in the Hobbit who turn to stone - no other types turn to stone)
 * Mountain Trolls (lived in the mountains, and pushed Grond)
 * Cave Trolls (attacked the fellowship in Moria)
 * Hill Trolls (lived in the Coldfells, one of these slew Aragorn's grandfather)
 * Snow Trolls (only mentioned as part of a legend, Helm Hammerhand, king of Rohan, was compared to one of these - so they may or may not have really existed)
 * Olog-hai (a type of troll which were found in both Mordor and Mirkwood)

There were also Troll-men and Half-trolls, which may or may not have been two names for the same thing.

Source: http://tolkiengateway.net/wiki/Trolls