WordNet sense 1 (an informal body of friends):

crew, crowd

WordNet sense 2 (a grouping of a number of similar things):

clump, cluster, clustering

WordNet sense 3 (any collection in its entirety):

caboodle, lot

WordNet sense 4 (form into a bunch):

bunch together, bunch up

WordNet sense 5 (gather or cause to gather into a cluster):

bundle