AT-RT

The All Terrain Recon Transport (AT-RT) is a one-man bipedal walker used for reconnaissance and patrolling, first by the Grand Army of the Republic during the Clone Wars, and later by the Galactic Empire and Alliance to Restore the Republic.

Star Wars Lore
Due to its light build, AT-RT walkers were extremely vulnerable to hard-hitting weapons. This led many commanders to use them in fast scout packs or in the role of civilian (police or military) support. Commonly, these walkers operated as picket and pathfinder units.

AT-RT walkers were first used during the Battle of Kashyyyk, and were later used in a try to track down Jedi Master Yoda after Order 66 was announced.

They also saw use on Outer Rim planets like Utapau and Mygeeto.

These light-weight walkers would also be utilized on the attack on the Jedi Temple. A year later, during an attempt by ex-Jedi Fy-Tor-Ana and Ferus Olin to retrieve a cache of lightsabers from the occupied Temple, AT-RTs would back up squads of stormtroopers that were hunting them.

During the Galactic Civil War, modified AT-RTs would also be used by the Rebel Alliance. Many of these walkers were painted in camo blend in with their surroundings. A floodlight often replaced the repeating blaster cannon, providing additional aide for the walker on night-time missions, but making the vehicle more vulnerable in the process.