One of the surviving fragments of the laws of Solon lays down which groups could have their own regulations, providing of course that these did not clash with the laws of the polis. The list includes broader groups such as demes and phratriai, and others with specific goals and a smaller number of members, such as traders and hoi epi leian oichomenoi, in other words pirates. The fact that the lawgiver was concerned with their organization shows that such groups, though untypical, were in existence in his day.

Orgeones was the name for members of groups (the groups themselves having no recorded name) formed for the purpose of private cult activity connected with heroes and minor deities. The relation of the orgeones to other groups is not perfectly clear. It was, according to Philochorus, the phratriai that had the obligation of welcoming the orgeones, as well as the gennetes. It seems as if the member's status was hereditary, and the witness of the orgeones, along with that of the phratores and the demotai, was used as proof in cases of adoption. They were not, however, subdivisions of the phratria, inasmuch as they could also include members of different phratriai, and (in the Classical period) even women and metics. Lastly, they had the right to own property and to bring actions in the courts.

Similar were the functions of the thiasoi, whose cult could also be related to major gods and heroes like Dionysus or Heracles. All the references to, and inscriptions about, the thiasoi come from the Classical period, but there is no information about their initial appearance. They were organizations of a hereditary nature and, in the Classical period at least, they took as members even children (or, according to another interpretation, slaves). They held joint messes and are referred to as syssitoi or homotaphoi if they had a common location and burial customs.