Adam and Eve have liturgical feast days, so do Isaiah, Jeremiah, King David and many others.
We in the West have not discussed it much, but the Eastern Churches remember them every year.
The Catechism of the Catholic Church states,
“The patriarchs, prophets, and certain other Old Testament figures have been and always will be honored as saints in all the Church’s liturgical traditions” (CCC 61).
Here is an interesting article in the newsletter of the Association of Hebrew Catholics.
It not only explains the “sainthood” of Old Testament heroes, but gives a list of the dates for various prophets, kings, and virtuous men and women before Christ.
For the article and the calendar, click here.