They aggregate in clusters much like the stars that comprise them. And just like those star clusters, there are different kinds of galaxy clusters. There are groups, which may contain from a handful to a few dozen galaxies. These groups are gravitationally bound, which means all the galaxies move in complex orbits around each other. Sometimes the group members can collide.
Galaxies also appear in larger clusters.
The nearest such cluster lies in the direction of the constellation Virgo, and has hundreds and even thousands of galaxies in it. The largest is a monster elliptical that may have as many as a trillion stars in it, making it twice the size of our own Galaxy. This cluster of galaxies is so enormous in extent that even though it lies XXX million light years away, it occupies a large area of sky as seen from the Earth. But even the Virgo Cluster is small potatoes. There are vast clusters of clusters, called superclusters, which contains hundreds of thousands or even millions of galaxies.