Yes, the Catholic Church has the tradition of seeing the righteous in the Old Testament as saints. We call them Patriarchs (like Adam, Abraham, etc.) and Prophets (Elijah, Jeremiah, etc.) We believe they are in heaven and they Feature in our liturgical and devotional prayers.

Honestly, I also wonder why we don’t say St. Moses or St. David etc., and although we actually have many of their feast days, we don’t celebrate them. However, in the Church’s monastic tradition, they are called saints and many of their feast days are still being celebrated.