due to the abnormal amount of background Arcane Radiation on Terra, it is possible to get some...interesting crossbreeds between species that would otherwise never be able to successfully breed, let alone create fertile offspring, here are a list of some known or theoretical crossbreeds:

Kirin:

An adolescent dragon-Unicorn Kirin
*Not to be confused with the Qirins of Neighpan*
A union between any type of equine and a dragon, Kirins were last in abundance about 500 years ago, but have since declined in number to a few individuals every generation, the reason for this remains a mystery. Inherited traits of ponies are often hit and miss, some are born with unicorn horns, yet are unable too use magic, and it's a 50/50 chance of a Kirin earning a Cutie mark ever, let alone in the first ten years of their life. Kirins usually grow to be bipedal (although there are exceptions) and between 6-7ft tall and have lifespans in the realm of that of dragons and Alicorns

If a Kirin is of the winged persuasion, then more often than not they will have the proportions of dragon wings, regardless of whether they are feathered or draconic, for instance an adult Kirin with have a wingspan approaching 20-30ft. For this reason most will fold their wings around them like some sort of cape.

Hippogriff:

A hippogriff with a ratio of 60% Pony to 40% Griffin
A union between an Equine and a Griffin, this crossbreed is just as rare, if-not rarer than Kirins, those that do exist are often shunned due to the tensions between Equestria and the Griffin Kingdom, it is for this reason that they are also rare.

Neue-Toa:

whilst not technically a crossbreed, as Toa are totally mechanical, and Neue-Toa are magically created from a pre-existing individual. they are still worth mentioning. Neue-Toa often take the form of the Bipedal or 'anthro' form of a species if said species is a quadruped, their joints will also become mechanical