I know that they didn't celebrate Christmas, Easter, Pentecost, All Saints, Saints' Days etc.
What exactly was their rationale for not celebrating (for example) Easter or Whitsun? Fundamentalist Protestants today who refuse to celebrate those holidays tend to do so because of their alleged 'connection' to ancient Babylonian fertility/solar religion. Did the 17th century Puritans really buy into all that Easter = Ishtar stuff? If so, then surely the more educated among them must have realised that it wasn't true?
Did they have any other festivities to celebrate? Surely they must have brought up Christ's death and resurrection on Easter, when they were preaching in church? Or did they deliberately avoid mentioning it on that specific day?
We do know they celebrated more secular festivals, like a Harvest festival. And Thanksgivings were days of feasting. It wasn't that the bible "buy into" anything. They were being what they felt were in the bible. They intended to be "pure" in their faith. They felt that there had been too much "dressing up" of certain days which allowed people to not properly reflect on the Lord's Day. Because there was no scriptural command to celebrate any of these days, as there was to celebrate the Lord's Day, celebrating them would have bene straying from a pure intentional understanding of the New Testament. It's for this same reason that marriage was not a sacrament to the Puritans. A marriage was performed by a Justice and was considered a legal contract. This is why in areas settled by the Puritans and their descendants it was easier to get a divorce (still not easy, but easier) than in any other part of the country.