Queen Cleopatra of Egypt named her twins (boy/girl):
Alexandros Helios (meaning "man-protector" "sun")
Cleopatra Selene (meaning "father's glory" "moon")
(The ancient greek god of sun Helios and the ancient greek godess of the moon Selene were also siblings).
Other famous twins were (Helen's brothers) Castor and Polydeukes, Apollo-Artemis, Lynceus and Idas, Hilaeira and Phoebe, Zetes and Kalais, Hercules and Iphicles (Iolaus'father), Pelias and Neleus, Danaos and Aegyptos etc.
Other twin brothers were Hypnos (sleep) and Thanatos (death) but are not suitable for naming children...