Here is a list of trinities in various religions:
The Classical Greek Olympic triad of Zeus (king of the gods), Athena (goddess of war and intellect) and Apollo (god of the sun, culture and music)
The Delian chief triad of Leto (mother), Artemis (daughter) and Apollo (son) and second Delian triad of Athena, Zeus and Hera
The Olympian demiurgic triad in platonic philosophy, made up of Zeus (considered the Zeus [king of the gods] of the Heavens), Poseidon (Zeus of the seas) and Pluto/Hades (Zeus of the underworld), all considered in the end to be a monad and the same Zeus.
The Titanic demiurgic triad of Helios (sun when in the sky), Apollo (sun seen in our world) and Dionysus (god of mysteries, "sun" of the underworld) (see Phaed in Dionysus and the Titans)
The ancient Egyptian triads:
Osiris (husband), Isis (wife), and Horus (son)
The Theban triad of Amun, Mut and Khonsu
The Memphite triad of Ptah, Sekhmet and Nefertem
The Elephantine triad of Khnum (god of the source of the Nile river), Satet (the personification of the floods of the Nile river), and Anuket (the Goddess of the nile river).
The sungod Ra, whose form in the morning was Kheper, at noon Re-Horakhty and in the evening Atum, and many others.
The Hellenistic Egypt triad of Isis, Alexandrian Serapis and Harpocrates (a Hellenized version of the already referred Isis-Osiris-Horus triad), though in the early Ptolemaic period Serapis, Isis and Apollo (who was though sometimes identified with Horus) were preferred.
The Roman Capitoline Triad of Jupiter (father), Juno (wife), and Minerva (daughter)
The Roman pleibian triad of Ceres, Liber Pater and Libera (or its Greek counterpart with Demeter, Dionysos and Kore)
The Julian triads of the early Roman Principate:
Venus Genetrix, Divus Iulius, and Clementia Caesaris
Divus Iulius, Divi filius and Genius Augusti
Eastern variants of the Julian triad, e.g. in Asia Minor: Dea Roma, Divus Iulius and Genius Augusti (or Divi filius)
The Matres (Deae Matres/Dea Matrona) in Roman mythology
The Fates, Moirae or Furies in Greek and Roman mythology: Clotho or Nona the Spinner, Lachesis or Decima the Weaver, and Atropos or Morta
the Cutter of the Threads of Life. One's Lifeline was Spun by Clotho,
Woven into the tapestry of Life by Lachesis, and the thread Cut by Atropos.
The Hooded Spirits or Genii Cucullati in Gallo-Roman times
The main supranational triad of the ancient Lusitanian mythology and religion and Portuguese neo-pagans made up of the couple Arentia and Arentius, Quangeius and Trebaruna, followed by a minor Gallaecian-Lusitanian triad of Bandua (under many natures), Nabia and Reve female nature: Reva
The sisters UksÃ¡hkkÃ¡, JuksÃ¡hkkÃ¡ and SÃ¡hrÃ¡hkkÃ¡ in SÃ¡mi mythology.
The triad of Al-Lat, Al-Uzza, and Manat in the time of Mohammed (Holy Qu'ran (Abdullah Yusuf Ali translation), Surah 53:19-22 )
Lugus (Esus, Toutatis and Taranis) in Celtic mythology
Odin, Vili and Ve in Germanic mythology
The Norns in Germanic mythology
The Triglav in Slavic mythology
Perkunas (god of heaven), Patrimpas (god of earth) and Pikuolis (god of death) in Prussian mythology
The Zorya or Auroras in Slavic mythology
The Charites or Graces in Greek mythology
The One, the Thought (or Intellect) and the Soul in Neoplatonism
The Christian Trinity