Shipping is a given in any fandom. The Yaoi, Yuri, and Het communities will descend on any work to bring their favorite pairings together.
However, they will typically gravitate towards whatever shows offer the most choices. If the main cast is primarily male, it will be male/male that dominates the popular ships. If the main cast is mostly female, it's mostly yuri. If the cast is pretty balanced in terms of gender, then ships will be predominately heterosexual.
-My Little Pony: Friendship is Magic: Mane 6 are all girls. Most ponies seen in show are girls. Primary type of ship? Girl/Girl.
-Pokemon: Balanced gender ratio. Ships of all types, but most are heterosexual.
-Avatar: The Last Airbender: Same as Pokemon, balanced gender ratio, so ships are het.