The tarot cards I use are designed around figures and concepts of Welsh mythology. The major arcana are basically as follows (mythic information mostly from wiki, for more detailed mythological info see links to sources):
The Magician - א - Gwydion
In Welsh mythology, Gwydion is a magician appearing prominently in the Fourth Branch of the Mabinogi and the ancient poem Cad Goddeu. He is the brother of Gilfaethwy and Arianrhod, and the nephew of Math fab Mathonwy. In the Mabinogion he is called the son of the goddess Dôn, making it likely he is an euhemerized god or demi-god.
Gwydion also appears in the 6th century poem Cad Goddeu (The Battle of the Trees), found in the Book of Taliesin. There he wins a battle against Bendigeidfran by animating an army of trees and guessing Bendigeidfran's name.
The Priestess - ב - Ceridwen
In Welsh medieval legend, Ceridwen was a magician, mother of Taliesin, Morfran, and a beautiful daughter Crearwy (or Creirwy). Her husband was Tegid Foel, and they lived near Bala Lake in Wales.
From the Welsh cerydd, "chiding love", and gwen, "white, blessed". The theonym appears to be derived from Romano-British *Caritavena, Proto-Celtic *Karjitā-wenā a feminine compound meaning "chastisement-love" or "chiding love" (cf. ).
Ceridwen plays a role in Wicca as a goddess, her cauldron symbolizing the feminine principle.
The Empress - ג - Rhiannon
In Welsh mythology, Rhiannon was a daughter of Hefeydd the Old. She was married to Pwyll and, later, Manawydan.
The name appears to be derived from Proto-Celtic *Rīganto-n-ā meaning "great queen" or, more literally, "feminine reigning [spirit]", *-n- being a Proto-Celtic infix denoting divinity (q.v.   ). Following accepted sound laws elucidating systematic diachronic phonological sound change in Celtic proto-linguistics (q.v.    ), the Romano-British form of this Proto-Celtic theonym is likely to have been Rīgantona.
The Emperor - ד - Bran The Blessed
Bran the Blessed (Welsh: Bendigeidfran, literally "Blessed Crow") is a giant and king of Britain in Welsh mythology. He appears in several of the Welsh Triads, but his most significant role is in the Second Branch of the Mabinogion, Branwen, daughter of Llyr. He is a son of Llyr and Penarddun, and the brother of Branwen, Manawydan, Nisien and Efnysien. The name "Bran" translates from Welsh as "Crow", often translated in the context of this tale a "Raven", as the name brân is the generic name for the genus Corvus.
The Hierophant - ה - Taliesin
Taliesin or Taliessin (c. 534 – c. 599) is the earliest poet of the Welsh language whose work has survived. His name is associated with the Book of Taliesin, a book of poems that was written down in the Middle Ages (John Gwenogvryn Evans dated it to around 1275). Most of the poems are quite late in date (around 10th to 12th century), but a few are earlier, and eleven of them, according to Ifor Williams, date from the 6th century. He is believed to have been a bard in the courts of at least three British kings of that era. In legend he attained the status "Chief Bard of Britain" and as such would have been responsible for judging poetry competitions among all the royal bards of Britain. A few of the marks awarded for poems are extant in the margins of manuscripts. Taliesin's life was later the subject of 16th century mythological work by Elis Gruffydd, who may have relied on existing oral tradition about him.
The Lovers - ו - The Dream Of Macsen Wledig
And he saw a dream. And this is the dream that he saw. He was journeying along the valley of the river towards its source; and he came to the highest mountain in the world. And he thought that the mountain was as high as the sky; and when he came over the mountain, it seemed to him that he went through the fairest and most level regions that man ever yet beheld, on the other side of the mountain. And he saw large and mighty rivers descending from the mountain to the sea, and towards the mouths of the rivers he proceeded. And as he journeyed thus, he came to the mouth of the largest river ever seen. And he beheld a great city at the entrance of the river, and a vast castle in the city, and he saw many high towers of various colours in the castle. And he saw a fleet at the mouth of the river, the largest ever seen. And he saw one ship among the fleet; larger was it by far, and fairer than all the others. Of such part of the ship as he could see above the water, one plank was gilded and the other silvered over. He saw a bridge of the bone of the whale from the ship to the land, and. he thought that he went along the bridge, and came into the ship. And a sail was hoisted on the ship, and along the sea and the ocean was it borne. Then it seemed that he came to the fairest island in the whole world, and he traversed the island from sea to sea, even to the furthest shore of the island. Valleys he saw, and steeps and rocks of wondrous height, and rugged precipices. Never yet saw he the like. And thence he beheld an island in the sea, facing this rugged land. see link for more ...
The Chariot - ז - Manawydan
In Welsh mythology, Manawydan, son of Llyr, is the equivalent of the Irish Manannan mac Lir and a presumed sea god.
Manawydan was a scholar, a magician, and a peaceful man.
Manawydan is one of the seven survivors of the second branch (of the Mabinogion).
Strength - ח - Twrch Trwyth
Twrch Trwyth is the name of a particularly potent wild boar Culhwch is instructed to hunt in the Middle Welsh prose tale Culhwch and Olwen. Twrch is named as the son of Prince Tared, cursed into the form of a wild creature; he has poisonous bristles, and carries a pair of scissors, a comb and a razor on his head, between his ears.
"Twrch" means "burrower, pig, mole" in Welsh, but Twrch Trwyth probably comes from Old Irish Orc tréith "Triath's boar" into early Welsh as (t)orc treth-i > "Trwyth's boar". The Irish version is found in Cormac's Irish Glossary.
The Hermit - ט - Myrddin
Myrddin Wyllt or Merlinus Caledonensis is a figure in medieval Welsh legend, known as a prophet and a madman. He is the most important prototype for the modern composite image of Merlin, the wizard from Arthurian legend.
Myrddin Wyllt appears to have been a historical person living in 6th century Britain. He was probably born sometime around AD 540. He is said to have had a twin sister called Gwenddydd. Myrddin Wyllt is said to have gone mad after a certain battle in AD 573. He fled into the forest and lived with the animals. There he is said to found his gift of prophecy.
Myrddin reportedly prophesied that he himself would die by falling, stabbing and drowning. This was fulfilled when a gang of jeering shepherds drove him off a cliff, where he was impaled on a stake left by fishermen, and died with his head below water. His grave is reputed to lie near the River Tweed in the village of Drumelzier near Selkirk, although nothing remains above ground level at the site.
Wheel Of Fortune - י - Arianrhod
Arianrhod ("silver wheel") is a figure in Welsh mythology who plays her most important role in the Fourth Branch of the Mabinogion. She is the daughter of Dôn and the sister of Gwydion and Gilfaethwy; the Welsh Triads give her father as Beli Mawr In the Mabinogion her uncle Math ap Mathonwy is the King of Gwynedd, and during the course of the story she gives birth to two sons, Dylan Eil Ton and Lleu Llaw Gyffes, through magical means.
The name "Arianrhod" (from the Welsh arian, "silver", and rhawd, "wheel") may have been derived from Proto-Celtic *Arganto-rotā, meaning "silver wheel". Alternately, the earliest form of the name may have been Aranrot, in which case the first part of the name would be related to "Aran". 
Justice - כ - Lady Of The Fountain
Owain, or the Lady of the Fountain is one of the Three Welsh Romances associated with the Mabinogion. It is analogous to Chrétien de Troyes' Old French poem Yvain, the Knight of the Lion. It survives in the White Book of Rhydderch and the Red Book of Hergest, both from the 14th century.
The tale's hero, Owain, is based on the historical figure Owain mab Urien. The romance consists of a hero marrying his love, the Lady of the Fountain, but losing her when he neglects her for knighly exploits. With the aid of a lion he saves from a serpent, he finds a balance between his marital and social duties and rejoins his wife.