Sui generis
In local government, a "sui generis" entity is one that does not fit with the general scheme of local governance of a country. For example in England, the City of London and the Isles of Scilly are the two "sui generis" localities, as their forms of local government are both (for historical or geographical reasons) very different from those of elsewhere in the country. 
In a press conference during which reporters were trying to analyse his political personality, Huey Long said, "...say that I am "sui generus", and let it go at that."
Professional services networks
Professional service networks are sui generis, and each network is formed for a different reason. Current and potential members are attracted to networks in which they can pursue their own individual objectives. While networks clearly do have things in common, each must be viewed in the context of its uniqueness. A successful network is one that meets the expectations of all of its members.