No, Saint Nicholas is not the patron saint of thieves. He is the patron saint of children, sailors, and the falsely accused.
Saint Nicholas of Myra is the patron saint of children, scholars and penitent thieves as well as a number of other causes. For a complete list of his patronages, click on this link.
In Roman mythology, the patron of thieves was the god Mercury.
The patron saints of murderers are:CaedwallaGuntramnusJulian the HospitallerNicholas of MyraSolomonVladimirAs per the Patron Saint Index
Saint Dismas is known as the patron saint of criminals and prisoners. He is revered for his repentance and acceptance of Jesus Christ while being crucified alongside him. Saint Dismas is often invoked for intercession by those seeking forgiveness and guidance in times of trouble.
The Patron Saint Inex lists no patron saints of bears.
A patron saint is supposed to be a protector in the Catholic religion. Patron Saint Angelico is the patron saint of artists. A patron saint is a protector of life.
As per the Patron Saint Index, there is no patron saint of wrestlers. However, Saint Sebastian is the patron saint of all athletics and athletes.
Saint Lillian is not a patron saint as per the Patron Saint Index.
There is a patron saint of Wales but no patron saint of whales.
There is no patron saint of color.
There is no patron saint of voting.