In researching some updates of the first books in the Sequetus Series I was interested in what are termed trojans, which are small planetoids, maybe some as big at planets, and they are plentiful in our solar system. Here is some information about them in the orbit of Jupiter.
There are estimated to be over a million trojans that orbit the sun, along with Jupiter, and they hang together in three clumps, and while not equidistant they form three main groups. They are the Trojans, the Greeks and the Hildas. The first Jupiter trojan discovered, 588 Achilles, and was spotted in 1906 by German astronomer Max Wolf. A total of 6,515 Jupiter trojans have been found as of May 2017. They are in effect, resembling a second asteroid belt.
Estimates of the total number of Jupiter trojans are based on deep surveys of limited areas of the sky. The L4 swarm is believed to hold between 160–240,000 asteroids with diameters larger than 2 km and about 600,000 with diameters larger than 1 km. See the diagrams and also see the Wikipedia references.
Of course the question then is, if Pluto is not a planet because it has not cleared its orbit of other bodies, is Saturn a planet or not?