There are several sets of twins on the roles of the saints, and other holy folks with a connection to twins. They include
Saint Protase and Saint Gervase were twin brothers, the children of saints, and both martyred.
Saint Benedict of Nursia and his sister Saint Scholastica were twins and both leaders of religious congregations, and Benedict was the author of the Benedictine Rule
Saint Angelus of Jerusalem had a twin brother who became a Carmelite brother, but who did not follow Angelus to canonization.
Saint Thomas the Apostle, the famous Doubting Thomas, may well have been so named because he was a twin (thomas = twin).
Though an only child, Saint Rita of Cascia was the mother of twin sons.
The most famous twins were the miraculous healers Saint Damian and Saint Cosmas, physicians who even performed a miraculous transplant.
Saints Mark and Marcellian were twin sons of a Saint, became deacons togethere and were martyred together.
And for a girls-only touch, both Blessed Margarita de Maturana and her twin sister became Carmelites.
There may be others, but these are all I have found so far.