I can find no saint named Sean. There is, however, Camille Saint-Saëns who is not a saint but a composer.
No, there is no patron saint of billiards.
Archangels are patron saints but do not have patron saints
The patron saint of your diocese would be the patron for the town. What is the name of your cathedral? That would be your patron.
The Patron Saint Index lists no patron saint of dinosaurs.
The Patron Saint Inex lists no patron saints of bears.
There is no patron saint of bullying or against bullying.
There is a patron saint of Wales but no patron saint of whales.
There are patron saints of schools and patron saints of artists but no patron saint of art schools.
There is no patron saint of color.
There is no patron saint of business. However, there are patron saints of merchants.
There is no patron saint of voting.
There is no patron saint of hair but there are patron saints of hairdressers.