Such a variety might provoke calls to merge and worries about duplication in Whitehall, but the epilepsy sector has successfully funnelled collaborative activities through an umbrella body: the Joint Epilepsy Council.
"We're unusual in that there is a proliferation of epilepsy charities," says the council's general secretary, Sharon Harvey. "With other conditions there seems to be one major charity, and that's it."
The council represents 22 organisations in the epilepsy field, from large bodies such as the National Society for Epilepsy to smaller research charities and regional and town-wide groups.
The council has shared its activities among five working groups, covering areas such as health policy, residential care, research and education.
The groups meet at least three times a year.
The health policy group concentrates on campaigning and works with the all-party groups on epilepsy at Westminster, the Scottish Parliament and the Welsh Assembly. It is currently campaigning against proposals to reduce the number of specialist epilepsy nurses.
The campaigning work of the council helped to bring about National Institute for Clinical Excellence guidelines on epilepsy. "They are vastly improving treatment," says Harvey.
Two of the council's smaller members are contemplating merger, but Harvey says council membership enables charities to maximise their effectiveness without amalgamating.
And she says epilepsy charities are keen to work for the common good.
"Members will offer help in terms of staff and expertise when they could be ploughing their own furrows," she says.
Case study provided by the NCVO's collaborative working unit.