Goblins are one of the stronger factions and can be formidable foes in any game where they make a presence.
Their Swamp Mastery ability makes them very fast at Earth terrain, as they can use melee icons as maneuvers. Their heavy melee units become faster than most cavalry, making them incredibly tough to stop when they get moving.
The Foul Stench ability is also a powerhouse when it gets set up properly, as it prevents a number of opposing units from counter-attacking. This creates a perfect storm for fast, hard-hitting melee units.
Trolls bring a degree of resilience most armies dream of, allowing them to repopulate an army with a couple of well-timed Regenerate triggers, which can fire on almost any roll.
They are truly masters of melee combat, with the Scent of Fear and Decay spells, especially considering their faction abilities which allow them to avoid taking as many cavalry units as other factions might.
The Leopard Rider is an army-in-a-can, with Rend providing both maneuvers to control terrain and a high ceiling for damage.