Cherubs

Cuddly and cute, Cherubs are a race of kitten-like creatures with a sickeningly sweet outlook on life. They live on the outskirts of Equestria, and are only technically citizens of Equestria. Much like ants, Cherubs can build incredible (if too cutesy) buildings, despite their low intelligence level.Despite semi literacy rates of above 50%, Cherubs are rather naive, and their intelligence is about that of a first grader at their smartest. They are creatures built out of affection and love, their naivety and sweet outlook can be exploited, and have been in the past by Equestria, but it's no longer legal due to their intelligence level qualifying them as creatures that are unable to give consent or understand the ramifications of agreements.
There are three species of Cherubs, or rather, three distinct breeds. Those with hearts on their belly can emit small amounts of magic, mostly in the form of bubbles of magic. Those with fluffy ears are stronger and more intelligent than their other counterparts. Those without stripes or hearts are equivalent to earth ponies, they can forage for food better than the others. Despite their differences, Cherubs refuse to differentiate between the breeds, which, while keeping from discrimination, also keeps them from using their talents.
Most species consider them little more than a nuisance, their sweet nature and stupidity make them hard to be around, though they shower any new creature in gifts, they never stop helping others, even if you don't want their help. They were enslaved by Changelings on and off for a few years, before a crystal heart-like device was placed in their city, powered by their love, it keeps changelings at bay.

FEEL FREE TO USE THIS CONCEPT, AS IT'S NOT QUITE MINE, IT'S CANON TO THE MLP COMICS.