The Wonderbolts were originally a pre-war group of aerial performers and in some cases, an emergency task-force employed by the Equestrian government.
See: The Wonderbolts on the My Little Pony wiki
The original Wonderbolts mainly performed and participated in aerial acrobatic shows or competitive races. They also seemed to be some form of emergency task force, employed to deal with high level threats. A trio of them were sent to deal with a rampaging Spike, who had become a ferocious, adult dragon. They managed to land a few blows on Spike, but were defeated relatively easily and imprisoned within the top half of a water tower.
During the WarEdit
The Wonderbolts were retired, swapped out for the infamous Shadowbolts. The Shadowbolts became a symbol of pre-war Equestria's dominance in aerial combat and were used as a morale boosting symbol.
After the War/Present DayEdit
The Wonderbolts were re-formed by the post-war pegasi government, the Grand Pegasus Enclave. The Enclave had the Wonderbolts perform in aerial shows to keep the Enclave populace placated. The post-war Wonderbolts were also trained and capable of achieving the speed necessary to perform the Sonic Rainboom. The Enclave also employed them as an elite core of assassins, but they could only operate with the Council's approval.
The Wonderbolts were sent to kill Littlepip and her companions, they were forced to follow them into Everfree Forest where they were trapped by Red Eye. The Wonderbolts were captured and forced to view memories of Calamity, that ultimately changed their view of him and made them decide not to continue their pursuit of him.
In Other StoriesEdit
|Wonderbolts in Fallout: Equestria - Outlaw|
The Wonderbolts are sent to hunt down Mach, after he kills another officer and becomes a Dashite. The Wonderbolts injure Mach whilst trying to kill him, but don't inspect the body due to their fear of surface contaminants and Mach being on Equestria's surface.
The Wonderbolts failure to kill Mach, leads the Enclave to first place a bounty on Mach and then deploy the Wonderbolts most elite assassin, the Wraithwing.