Being Scottish Celtic myself, the Celtic pantheon of Gods and Goddesses and their beliefs has always fascinated me.  There are several gods and goddesses and patrons in the Celtic pantheon that have similar duties or they share duties.
 

Aine: goddess of love and fertility
Amaethon: god of agriculture
Anu: earth goddess
Aonghus: god of love and courtesy
Arawn: god of the underworld
Arianrhod: goddess of destiny
Badb: goddess of battle
Balor: god of death
Belenus: god of the sun
Blodewuedd:  protectress of the wild world
Bran: god of inspiration, boundaries and guardianship
Brigantia: goddess of water, war, healing, and prosperity
Brighid/Brigit: goddess of healing, fertility, fosterage, learning, inspiration,
                               and smithcraft
Cernunnos: the horned god of the wild and the forest
Cerridwen: dark goddess of fertility
Cliodhna: goddess of beauty
Dagda: father of gods
Dian Ceht: god of healing
Donn: god of the dead
Epona: goddess of the horse
Goibhniu/Gofannon/Goibnu: the god of the smith and forge
Lir: sea god
Lugh/Llew: god of light, warmth, sun and inspiration
Mac Ceht: god of eloquence
Macha: goddess of battle
Manannan MacLir/Manawyddan: god of the sea
Morrighan: goddess of war
Nemain: goddess of war
Nodens: British god of healing
Ogma/Oghma/Ogmios: god of eloquence and persuasive discourse
Rhiannon: goddess of horses and the sacred land
Taranis: god of thunder
Tigernonos: primal god