The brief response with a link to the Mayflower Society of Descendants webpage may not be helpful to those who are not already members of that society. I am assuming the questioner is not asking if the MFSD holds reunions. It is a non profit with chapters usually called state societies which hold two meetings a year, while the national society holds one meeting each year around the country, with every third year in Plymouth. But I think the better answer is that besides the MFSD, there are also family societies, that are affiliated with but not part of MFSD. In other words, if you are a Howland descendant, as I am, you can join the Howland society, and they hold an annual meeting which might be called a "reunion". The advantage to a family like those on the Mayflower is that we have a large pool of known descendants, and a number of professional genealogists working on these families. So we have a core group of Howland descendants who can do more than just have an annual picnic. We can fund projects which keep improving the knowledge of our ancestors. Example; The Howland society has purchased the home property of John Howland in Rocky Nook, and has been doing archeological digs there. So we know where the hearth was, and where the entrance way was. It was a great thrill to walk there with a group of Howland descendants, none of whom I'd ever seen before, and cross the threshold of our mutual distant ancestor's home. I don't know if all the MPs who left descendants have a family society, but most do. Many of them hold their meetings in summer or early fall, the latter to coincide with when the MFSD holds their congress in Plymouth, every third year. Names to look for: The Warren Cousins, The Pilgrim John Howland Society, The Elder William Brewster Society, Soule Kindred in America, Alden Kindred of America... the list is much longer than this.