Celtic Deities
Angus of the Brugh - (Oengus of the Bruig - mac Oc meaning 'young son')Father - Dagda, mother - Boannan
Arawn - God of Annwn (the Underworld)
Arianrhod - meaning either 'silver wheel' or 'high fruitful mother' daughter of don
Artio - Goddess of the Bear cult (similar to Artemis the Greek goddess)
The Badb - Red mouthed, bird shaped Goddess of War one of the Morrigan triad
Belatucadros - meaning 'fair shining one'. Horned god of war often equated with the Roman God Mars
Belenus - Bel, Belinus meaning 'shining'. Celtic fire or solar god, often equated with Apollo
Broannan - Goddess of the River Boyne, mother of Angus of the Brugh
Bodb - Irish Goddess of the battle
Bran - (The Blessed also meaning 'raven') hero god, brother of Manawydan ap Llyr
Branwen - Daughter of Llyr. One of the three matriarchs of Britain
Bres - Divine leader of the Tuatha De Danann
Brigantia - 'High One' Pastoral and river goddess
Brigit (Brigid) British/Irish Goddess of poets, healing and fertility
Cernunnos - Stag horned God of fertility and rebirth
Cerridwen (Caridwen/Ceridwyn/Kerridwen) - Celtic corn/dark moon Goddess of rebirth, wife of tegid Voel (lord of the Lake)
Coventina - Goddess of springs and waters
Creiddylad - (Cordelia) daughter of Llyr (Shakespeare wrote of Creiddylad and Llyr as Cordelia and Lear)
The Dagda - Irish Earth and father god
Danu - Celtic Mother Goddess, one of the Morrigan triad. Irish mother of the Tuatha De Danann
Dian Cecht - Healing God
Epona - Goddess of horses
Goibniu - God of smiths, one of the Tuatha De Danann (known as Govannon to the Welsh)
Gvenn Teir Bronn - Welsh triple breasted Goddess of motherhood
Gwydion - Welsh magician God
Hooded Spirits - Celtic triad of healing and fertility
Lir - Irish sea God (Llyr to the Welsh)
Lleu Llaw Gyffes - Welsh hero god (also known as Lug to the Celts)
Lug - Celtic hero god, Also known as.. Lugh, Lleu, Lleu Llaw Gyffes ('Bright one of the skillful hand'), Samildanach ('many skilled') and Find ('fair haired one')
Macha - ('crow') One aspect of the triple Morrigan. Celtic Goddess of war
Manannan mac lir - Celtic Fertility God of the sea. (Manawydan ap Llyr to the Welsh)
Manawydan ap Llyr - Welsh version of above
Math Mathonwy - Welsh sorcery God
Medb - Celtic Goddess of War
Midir - Chieftain god of the underworld
The Morrigan - Collective term for the triad of war Goddesses. Individually - Badb, Danu and Macha
Nuada - Argetlam - ('silver hand'), former leader of the Tuatha De Danann also known as Nud, Nodens, and Llud Llaw Ereint.
Ogmios, Ogma - Grianainech ('sun face') god of eloquence, inspiration and language
Pwyll - God of the underworld, known as Pwyll Pen Annwn ('Pwyll head of Annwn')
Tailtiu - Goddess of the Earth
Tuatha De Danann - The main family of Irish gods
Adapted from 'A guide to the Gods' by Richard Carlyon
I recommend this book for much much more information on these and other deities