232 Donphan

Counter is one of the best fast moves in the game and has the best overall performance.

The addition of Body Slam following the GBL Season 10 update is an improvement for Donphan, enabling it to access a decent Charged Move without consuming a large amount of energy. Play Rough is run to handle Dragon-types (and have great neutral damage). Heavy Slam is cheaper and effective for shield baits, but doesn't provide meaningful coverage. Earthquake is more useful in the higher leagues, being harder-hitting, and is especially important in Master to give a chance against Dialga.

Charm lets Donphan fulfill a more niche role, and sports extremely high damage output at the cost of very bad energy gains. Body Slam is needed for this moveset due to its lower energy cost, as poor energy generation makes it difficult to access Donphan's charge moves. Earthquake offers wide coverage backed by STAB. 

Donphan holds an interesting niche as one of the few non-Fighting-type Pokémon to learn Counter. However, its stat-weighting and poor meta matchups (Azumarill, Altaria, Medicham) make it a poor choice in most cases. Ground-typing is somewhat vulnerable against common typings, and Donphan lacks counter-coverage moves to fight back. A lack of a low energy charge move also limits Donphan's ability to bait and pressure shields, making it slower compared to other picks. 

Donphan is stronger in Ultra than Great, though it’s still not the best. Play Rough is not enough to save it from a loss against Giratina. Access to Charm enables very narrow wins against either Giratina, but loses almost everything else.

Dialga remains top threats in Master, which makes Donphan as a Counter user interesting. However, there are better choices. With a max CP of 3013, Donphan doesn't have the stats that many legendary Pokemon boast.