Hasbro Universe

The Hasbro Universe, also known as the IDW Hasbro Universe or the IDW Universe is the name of the shared universe/multiverse in which several Hasbro properties published by IDW Publishing take place in.

Celestia only knows if My Little Pony: Friendship is Magic is canon to the universe or not. Officially, it is not, but that hasn't stopped writers and artists writing in cameos and minor crossovers from time to time.

Kind of crossovers
It has been teased that My Little Pony may, in some way be connected to the Transformers franchise, but just how has never been clear. In the Transformers 2007 film, a character is seen holding a Generation 3 My Little Pony plush toy and a handful of pseudo-crossovers have been made over the years, such as:
 * A handful of Transformers Prime commercials where the Transformers would mention My Little Pony.
 * A series of covers where My Little Pony characters interacted with Transformers. These covers were titled:
 * Til All Are Fun
 * Friendship Through Tyranny
 * Operation: Raise Da Hoof
 * In addition, a cover with Rainbow Dash and Starscream hanging out was also published.
 * The AllSpark Almanac volume II featured Discord at Maccadam's Old Oil House on Cybertron.
 * Big Jim had a toy of Optimus Prime in his cave.
 * Transformers vs G.I. Joe #14 featured Megatron going to the planet of Unicorn where he was licked by ponies.
 * Synergy: A Hasbro Creators Showcase featured a piece of artwork in which Twilight Sparkle, Spike and Fluttershy interacted with the Holograms.
 * In fact, several Jem comics reference My Little Pony and Equestria Girls. Typically by having the characters cosplay as the ponies or buy Pony merchandise.

Actual crossovers
My Little Pony/Transformers: Friendship in Disguise and its sequel series, My Little Pony/Transformers: Magic of Cybertron are currently the 'most' official crossovers released. Before those, there was the Hasbro-wide crossover, When Worlds Collide, as well as the canceled Transformers x My Little Pony.