Space X Starlink satellites are in fact launched in formations, a bunch of units to be operated on essentially the same orbit are ejected from the main rocket in a kind of "trains" (like
this), then after they are freed they are maneuvered so they spread along the orbit into positions they are supposed to work.
Starlink is rather extreme, their "trains" count between 10..30 units, but many other launches of small satellites use similar concept, just with fewer units.