In my country, the UK, which - due in part to the first past the post electoral system - does not generally entertain diverse coalitions, I am not aware of any examples of 6-party coalitions. There have, however, been a few 5-party coalition governments, all under fairly exceptional circumstances.
The Churchill war ministry (1940-45) consisted of 5 parties, the Conservative Party, the Labour Party, the National Liberal Party, the Liberal Party, and the National Labour Party. Obviously, this is rather a poor example with two of the five parties having split from two of the others. In addition, this coalition took place under the circumstances of global war, and so is rather an exception to the rule.
The other examples are the 3rd, 4th and 6th Northern Ireland assemblies, which have all involved the DUP, Sinn Féin, the SDLP, the UUP and the Alliance Party within the governing executive. These are also fairly weak examples, as Northern Ireland’s system of government is based on a mandatory coalition, with ministerial positions being allocated based on representation in the Assembly under the D’Hondt system.