I remember a site that had a long list of themed names sorted by the number of elements in a set. Eg. 7 colours of a rainbow, 8 planets, etc. I lost it and can

I remember a site that had a long list of themed names sorted by the number of elements in a set. Eg. 7 colours of a rainbow, 8 planets, etc. I lost it and can't for the life of me remember what it was called. Anyone have an idea?