Elizabeth did have a brother, who ruled first - Edward VI. He had no children (didn't marry) and so his sisters took the throne in age order. Elizabeth didn't marry, but Mary did and couldn't produce an heir.
The following monarchs left no legitimate children:
William II
Richard I
Richard II
Henry VI
Edward V
Richard III
Edward VI
Mary I
Elizabeth I
Charles II
William III/Mary II
William IV (10 illegitimate)
Edward VIII
I saw that add in the paper:
Make money from home! Be your own boss! Thousands per day income potential. No experience required. Contact: Archbishop of Canterbury. No phone calls, EOE. Drug Free Workplace. Minorities encouraged to apply.