Moves
When coupled with entry hazards, Circle Throw works well to phaze opposing Pokemon, forcing them to take more damage every time they enter the field, and potentially stop weaker setup sweepers from boosting. Rest is Throh's only means of recovery, giving it longevity during the match. Sleep Talk allows Throh to not be passive after using Rest with the added benefit that moves selected by Sleep Talk will get an Attack boost from Guts. Bulk Up boosts Throh's Attack and Defense to very high levels and makes it hard to take down after a single boost. Knock Off allows Throh to hit Ghost-types that would otherwise wall it while also hitting Psychic-types such as Mesprit, Xatu, and Musharna and is overall useful for removing opposing Pokemon's items early-game. The inability to boost, however, is very troubling for Throh, and oftentimes it's better to just run a Pursuit trapper to deal with Ghost- and Psychic-type Pokemon.
Set Details
Maximum HP and Special Defense investment with a Careful nature allows Throh to make the most of its special bulk and allows it to set up on weaker special sweepers or phaze them. Guts is the preferred ability, as it boosts Throh's Attack when it's inflicted with status and pairs well with Rest as Throh's sole way to restore its health. Leftovers is the item of choice, as it increases Throh's longevity over the course of a battle.
Usage Tips
Use Throh to pivot into weaker attackers such as Lanturn, Piloswine, and Steelix early- and mid-game, allowing Throh to phaze them, remove their item with Knock Off, or use them as setup fodder. Throh functions best in the later stages of a game after opposing Psychic-, Poison-, and Ghost-types have been removed or severely weakened, as setting up early-game will almost always result in Throh being revenge killed. Throh's early- and mid-game offensive presence is almost nonexistent, as all it can hope to do is phaze opposing Pokemon with weak Circle Throws or potentially remove their items with Knock Off. Ghost-types completely shut down Throh if it doesn't have Knock Off, so it should not set up before they are eliminated. Use Rest whenever Throh is at low HP, but still beware of mindlessly clicking Rest, as it forces Throh to rely on Sleep Talk, which is rather unreliable. Throh also receives an Attack boost by virtue of Guts when asleep, which is always beneficial.
Team Options
Spikes support works incredibly well alongside Throh and is almost mandatory when using it; Pokemon such as Garbodor, Omastar, Ferroseed, and Roselia are quality setters that can assist in Throh's attempt to effectively shuffle an opposing team. In particular, Omastar's resistance to Flying-type moves from Pokemon such as Archeops and Ferroseed's resistance to Psychic-type moves from Pokemon such as Mesprit are very useful for Throh. Pursuit trappers such as Skuntank, Liepard, and Choice Band Scyther are also some of the best partners for Throh, as they not only eliminate the Ghost-types that prevent Throh from sweeping, but can also can deal with Psychic-types that plague Throh. Ghost-types that can block Rapid Spin to keep Spikes up such as Rotom, Gourgeist-XL, and Mismagius are terrific partners as well. Lastly, bulky Ground- and Rock-type Pokemon such as Piloswine, Steelix, and Rhydon can combat Flying-types such as Scyther and Archeops that force Throh out while also providing Stealth Rock to aid Throh's phazing capability.