Deep Kin - some kinds of trollkin living in deep underground caverns became better suited for such environment. Sharp senses, pale skin, more hunt-based than warfare lifestyle and greater deal of individualism from early stages of growth. They can be really resilient enemy yet underground in not most fertile place for motherceliums. Their lonely hunts rarely let them grow a lot, assumption is they bring leftovers to nests.
Rust Orcs - there is noted separate line of trollkin which produced rust-tinted orcs. These are very beastial and brutal and specifically set on finding other kinds of trollkin. They evolved into predator of their own cousins, often spoiling other motherceliums with their dead bodies to overtake them. They look like regular trollkin to non-rust ones - also goblin and troll stages don't carry rust characteristics which additionally complicates the spread. Gossip says some crafty wizard created them.