How many festivals are there in Islam?

The Muslim may note the large number of festivals that are observed among the Muslims nowadays, such as the Festival of Trees, Workers’ Day (May Day), the anniversary of the king’s accession to the throne, birthdays, etc… There is a long list of such days, but each of these is the innovation of the Jews, Christians and polytheists; they have no basis in Islam. There are no festivals in Islam apart from Eid al-Adha and Eid al-Fitr.
It was narrated that Anas ibn Maalik said: “During the Jaahiliyyah, the people had two days each year when they would play. When the Prophet (peace and blessings of Allaah be upon him) came to Madeenah he said, ‘You had two days on which you would play, but Allaah has given you something better than them: the day of al-Fitr and the day of al-Adha.” (Narrated by Abu Dawood, 1134; al-Nasaa’i, 1556; classed as saheeh by Shaykh al-Albaani).