Trojan asteroids are small bodies orbiting around the L4 or L5 Lagrangian points of a Sun-planet system. Because of their peculiar orbits, they provide key constraints to the Solar System evolution models.
Currently, there are over 7,000 trojans catalogued in the Solar System. Most of them share the orbit of Jupiter.
In other planetary orbits two Uranus trojans, nine Mars trojans, and 28 Neptune trojans have been found to date.
Regarding the orbit of our planet, for the moment astronomers know about two Earth trojans. The first one is 2010 TK7, discovered in 2010, and the second is 2020 XL5, detected in 2020 but whose trojan status was confirmed by scientists just recently.