Ponies are social and sociable creatures, and tend to form groups based on common interests. Some of the major ones are listed below.
The military forces of Equestria, although for decades now they have acted primarily as border guards and emergency response far more often than as professional soldiers. Members of the guard are drawn from any and all of the races who make up Equestria's varied population, and stationed across Equestria in bases and guard facilities. There are several elite units within the Guard.
The Wonderbolts are a squad of Pegasus ponies who perform aerial acrobatics and demonstrations. They are technically a unit of the Equestrian Air Guard, and have been occasionally called out to deal with threats that require extreme skill in flight.
The best of the best, these ponies are directly assigned to protect Their Royal Highnesses, Princesses Celestia and Luna, and can often be found stationed around Canterlot. The Royal Guard is divided into three details, each with their own particular responsibilities, although they share information freely.
The Solar Guard are Celestia's own bodyguard. Their history is rich with heroics, as their Princess is not one to lead from the rear, but in these days they are most commonly seen standing unflinching guard over the Princesses and Canterlot Castle, the enchantments on their armor making them appear nearly identical. The public face of the Solar Guard is only the shine on a much hotter fire, as they also do a great deal of work organizing and assisting local police forces behind the scenes, and have among their ranks a number of trusted members given free reign to operate with their own discretion to seek out threats to Equestria.
For a thousand years, the Lunar Guard stood in the shadow of their Solar brethren, watching through the long nights and seeking out and striking down threats to Equestria. With the return of Princess Luna, the dark watch have themselves been brought back into the public eye, as they once again serve as her honor guard. On formal occasions, the Lunar Guard are known for their ceremonial armor, which is often enchanted to grand them the intimidating illusion of bat wings.
The Lunar Guard also runs an extensive network of clandestine operatives, many retired Guardsmen or normal ponies who report any information of interest they come across back to the Guard.
The newest addition to the Royal Guard, the Crystal Guard perform much the same function as their counterparts, in service of the Crystal Empress. They are a young service, as their predecessors were defeated and outlawed when King Sombra seized power over the Crystal Empire, but the Equestrian Royal Guard's veterans have worked with them extensively to bring them up to speed.
Headquartered in Cloudsdale's Weather Factory, the EWS is responsible for the overall weather planning for the entirety of Equestria. Made up almost entirely of weather working pegasi and unicorns with compatible talents, the EWS has a centuries long track record of providing dependable weather services and doing everything in their power to combat any rogue weather that might cross Equestria's borders.
Each pony settlement has its own branch office of the EWS, although small villages may only merit a single full-time weather worker and rely on the part time assistance of every pegasus in the area for large projects.
The EWS also employs experts in extreme weather conditions who are assigned seasonally to areas such as the Swayback Mountains or Everfree Forest, where wild and hazardous weather may require search and rescue services.
The Knights are hoof-picked warriors chosen more for their personalities than their combat abilities, sworn personally to the Princesses. Things like humility, mercy, and intuition are somewhat uncommon among Ostfriesians, but required for one to even be considered for Knighthood. Potential Knights must pass a test, which involves overcoming a unique trial within a lucid dream after catching Mary (or Sue) and kissing her hoof.