There is no patron saint of golf. St. Sebastian is the patron saint of athletics. Another opinion: The patron saint of golfers is St. Andrew.
No, there is no patron saint of billiards.
Saint Kiara is a saint but she is not the patron of anything at this time sorry
St. Lucia Filippini is a saint but not a patron saint at this time.
The closest I can find is St Bernard of Menthon who is the patron saint of mountaineers.
David of Wales is the patron saint of doves.
The patron saint of all sports is St. Sebastian.
I don't know if runners have their own saint, but St. Sebastian is the Patron Saint of Athletes.
St. Isidore of Seville is the patron saint of the Internet.
There is no patron saint of tennis or tennis balls. All we have is St. Sebastian who is the patron saint of athletics and athletes.
Pope Saint Leo the Great is not a patron saint.
St. Teresa Redi is a saint but not a patron saint.