Original description:
 
The original My Little Maniraptor was meant to be a one-off thing, but it’s spun way out of control. Why am I doing this? Confound these ponies! Just to get these out of my system, I’ve done individual pictures for the various major, recurring characters of the show, with musings on how the show might work with maniraptors instead of ponies. (No, that’s no guarantee I might not do even more of these, but at least it’ll be a while before I do.)
 
When I drew the original My Little Maniraptor, I had to decide on what maniraptor body plans I’d use represent the differentiation between different types of ponies. There are no maniraptors that actually have horns, so caenagnathoid oviraptorosaurs, having bony crests, were the obvious choice to represent unicorns. Twilight is based primarily off tall-crested oviraptorids such as Nemegtomaia, the tall crest being a symbol of her magical prowess. (I wouldn’t say that crest size correlates absolutely with magical power in the My Little Maniraptor universe, but it works symbolically in a meta sense. I wouldn’t be surprised if under her hat Trixie had a relatively short crest as an indicator of how she’s not as powerful as she claims to be.)
 
Spike was harder. I needed to make him something very different from maniraptors, as how little ponies know about dragons is a plot point in the original show. I considered making him a mammal, but there are very few Mesozoic mammals that give off a convincing dragon vibe. In the end I made him a small ceratopsian - still a dinosaur, but a very derived member of the line least closely related to maniraptors. And while I was designing him, I remembered that basal ceratopsians had a pair of fang-like teeth just like the original Spike has. In addition, gastroliths are known for basal ceratopsians such as Psittacosaurus, and Spike eating gemstones can be seen as an extension of this.
 
The original Spike is a very young dragon, so that brings up the question of how adult dragons would be represented in My Little Maniraptor. One of the reasons why I chose ceratopsians to be dragons is because ceratopsians include both very small and very large taxa, though that doesn’t cover the flying. The best I can come up with is that most of the adult dragons we’ve seen in the original show would be winged ceratopsids. What about Spike’s adult form, however? In one episode he is artificially stimulated to grow into an adult, and assuming this form is the same as what he’d grow into at a more natural pace, he belongs to a wingless type of dragon, different from the other dragons we’ve seen. In My Little Maniraptor, Spike’s adult form would probably be similar to a very large protoceratopsid.
 
Ironically, part of what makes Spike useful as an assistant in the original show is that he has grasping hands, but in My Little Maniraptor he’d probably be a lot less dexterous than the maniraptors. Based on Psittacosaurus, his reach would be extremely limited and only useful for carrying things at best (hence, Twilight having to float the clipboard in front of him in my drawing). Even so, he still has magic fire breath, and having an extra beak around probably comes in handy.
 
Incidentally, maniraptors having grasping hands avoids having the equivalent of ponies not being able to hold things using their hooves. However, even the maniraptors would probably prefer using their mouths and feet (and magic, in the case of caenagnathoids) to manipulate objects and hands for carrying them instead. Realistically, most maniraptors would not be able to carry things one handed (except by holding them to the chest), but I can see liberties being taken with this based on the fact that Bambiraptor was capable of doing so. Similarly, flying deinonychosaurs in My Little Maniraptor may use their feet for carrying things, although I question whether this was possible in life. (As alluded to earlier, most maniraptors, even those without backward-facing halluces, can curl their toes enough to grab onto things, and the first toe of deinonychosaurs can oppose the others to a degree. However, I doubt the utility of either option in flight, and the latter adaptation in particular appears to have been used for pinning prey to the ground, so even if a deinonychosaur could pick something up this way it would have had to be something they didn’t mind impaling.)
 
Also, Twilight Sparkle is best pony… uh, maniraptor.
 
Post-update notice: So, princess!Twilight. Her wings are larger now to sustain flight and I’ve given her retractable second toes to reflect characteristics from other types of maniraptors (as with the other princesses). That said, I’m obliged to mention that there’s one oviraptorosaur, Wulatelong, that may preserve a retracted second toe, but whether this represents a natural pose in life is up to further study. (Disappointingly, this is not even mentioned in the paper describing it!)