Speedsters is a loose group of speed endowed individuals who derive their abilities from an extra-dimensional energy source generated by Barry Allen and known as the Speed Force.
Beginning in The Flash Volume 2, the speedsters occasionally team up to stop greater enemies and solve the mysteries of the Speed Force itself.
The first appearance as a team was during "The Return of Barry Allen" in The Flash Volume 2 #74-79.
Over the course of The Flash Volume 2 many Flashes and speedsters are gathered to fight crime and solve mysteries together - Wally West, Jay Garrick, Johnny Quick, Max Mercury, Bart Allen (Impulse), Jesse Chambers, among others. They learn more and more about their ability and the energy source, the Speed Force, that's connects them, and to which Wally has the strongest connection. Later on, they learn how to channel their power and speed for Wally so he can run even faster as well as further back and forth in the time-stream.
In Terminal Velocity Max Mercury tells the group he was once called Windrunner and Quicksilver before calling himself Max Mercury, and the group realized Max must be one of the first speedsters who traveled forward in time but failed to merge with the Speed Force, something that Wally West is able to in the aftermath of Zero Hour.
In Dead Heat, some speedsters lose their ability temporarily, while Max Mercury seems to disappear inside the Speed Force, and Johnny Quick is killed.
Major Story Arcs
The Return of Barry Allen
When Barry Allen apparently returns from the dead and teams up with Wally West to fight crime together, Wally remains skeptical. When Barry starts taking all the credit and eventually announces he is the one and only Flash - throwing Wally into an identity crisis - Jay Garrick reaches out to Johnny Quick and Max Mercury to stop Barry Allen. Later, Wally West reveals the true identity of the Barry imposter to be Professor Zoom; together with the other three and the help of Hal Jordan he eventually defeats the imposter.
(The Flash v2 #74-79; Green Lantern v3 #40)
After the events of Zero Hour Wally is seized by a mysterious force and lobbed into a time-stream seeing unpleasant glimpses of the past and the future. He manages to return to the present but discovers there's something wrong with him. While his condition is getting worse and conflicting his relationship with Linda Park and Bart Allen (Impulse), a terrorist organization known as Kobra is threatening Keystone City. Wally calls the other speedsters - including Jay, Bart, Max Mercury, Johnny Quick, and Jesse Chambers - for help. Together they try to save the city and solve the mystery of the Speed Force - the power source that connects them.
(The Flash v2 #95-100)
The Speedsters are called together again when a cult of speed arises led by Savitar, a corrupt master of speed, who believes speed is the ultimate paradise and will stop at nothing to access it. With the help of Christina Alexandrova he tries to take full control of the Speed Force. When Wally finds out Savitar can use the Speed Force in ways he never dreamed of, he teams up with Bart Allen, Jessy Chambers, Max Mercury, Jay Garrick, and Johnny Quick, to defeat Savitar. However, Johnny Quick is killed in the battle, Max Mercury disappears in the Speed Force, and Wally, in order to end Savitar's madness, pushes Savitar right into the speed force where he remains trapped within its energy field.
(The Flash v2 #108-111; Impulse #10-11)
When Cobalt Blue attacks the city, Wally discovers, Cobalt Blue actually is Barry Allen's long lost and twisted twin brother, Malcolm Thawne, who has sworn vengeance against all Flashes past and present. Cobalt Blue uses a mystic gem and its sinister magic to curse and doom the entire Allen legacy. This curse promises the death of two Flashes before Barry Allen dies in the far future. Wally uses the power and aid of the other speedsters to race forward into the future warning the Flashes of each generation, and to defeat Cobalt Blue.
(The Flash v2 #145-150)
Blitz: The Origin of Zoom!
Hunter Zolomon, in an attempt to go back into time and regain his legs, ends up destroying the Cosmic Treadmill and getting infused with time. Zolomon becomes Zoom, but his speed is based on bursts forward in time and space instead of actual speed. His goal is to make Wally a better hero through Adversity. The speedsters gather in order to channel their speed into Wally so that Wally can move faster than Zoom. In doing this, Wally catches Zoom and forces him to freeze between times in a rift caused by Zoom's speed.
(The Flash v2 #197-200)
During the Infinite Crisis the Flashes finally help putting Superboy-Prime in a place where he can't escape anymore. The speedster, including the ones already within the Speed Force, channel their highest speed once again to pull Superboy-Prime into and trap inside the Speed Force.