See linked sources for more detailed information.
The Hanged Man - ל - Enchantment Of Dyfed
(Llewellyn Tarot Companion) "The land of Dyfed was known to be susceptible to the influence of the Otherworld, having shifting or overlapping boundaries between the two realms."
The Four Branches of the Mabinogi are the best known tales from the medieval Welsh Mabinogion. The word "Mabinogi" originally designated only these four tales, which are really parts or 'branches' of a single work, rather than the whole collection.
The most mythological stories contained in the Mabinogion collection are the four interrelated tales, by a single author or storyteller, titled The Mabinogi in the manuscripts, or currently often "The Four Branches of the Mabinogi". The use of characters' names as titles for each branch is also a modern practice; they are not so named in the original manuscripts. One figure, Pryderi appears in all four branches, though not always as a central character.
First Branch: Pwyll, Prince of Dyfed; which tells of Pryderi's parents and his birth, loss and recovery.
Second Branch: Branwen, Daughter of Llyr; which is mostly about events following Branwen's marriage to the King of Ireland. Pryderi is named but does not play a part in the tale.
Third Branch: Manawydan, son of Llyr; Pryderi returns home with Manawydan, brother of Branwen. Misfortunes follow them there.
Fourth Branch: Math, son of Mathonwy; about Math and Gwydion, who come into conflict with Pryderi.
Death - מ - Arawn
In Welsh mythology, Arawn was the Lord of the Underworld, which was called Annwn.
In Welsh folklore, Arawn rides with his white, red-eared hounds (the Cŵn Annwn or Hounds of Annwn) through the skies in autumn, winter, and early spring.
The baying of the hounds is identified with the crying of wild geese as they migrate, and the quarry of the hounds are the wandering Otherworld Spirits (possibly fairies), being chased back to Annwn (sometimes to the abode of the Brenin Llwyd or Grey King). Later the relevant mythology was altered to describe the "capturing of human souls and the chasing of "damned souls" to Annwn"; Annwn was inaccurately revised in some variants of Welsh mythology and described as being "Hell."
Temperance - נ - Keeper Of The Well
In the legend of Cantre’r Gwaelod, a lost land of Cardigan Bay is defended by embankments and sluices. The keeper of the embankement, Seithennin, is said to have drunk too much after a banquet and left open the sluices. The sea broke through and only a few inhabitants escaped from drowning.
Seithennin is the name of a poem in the Llyfr Du Caerfyrddin (Black Book of Carmarthen), as well as the poem's protagonist.
The poem details the inundation of the Drowned Hundred (Welsh: Cantre'r Gwaelod) or Plain of Gwyddno (Welsh: Maes Gwyddno - named for its ruler Gwyddno Garanhir, Seithennin's likely contemporary), believed to lie off the coast of Gwynedd, Wales underneath Cardigan Bay, which folklore blames upon the person of Seithennin.
This Seithennin, son of Seithyn Saidi, was Lord High Commissioner of the Royal Embankment and, as such, it was his failure to discharge his duties which led to the drowning of the Cantre'r Gwaelod. Seithennin is also listed in the Triads of the Island of Britain as one of the Three Immortal Drunkards of the Isle of Britain.
The name is also spelled Seithenyn or Seithenhin.
The Horned One - ס - The Wild Herdsman
This archetypal character appears in the person of Custennin, in the story of CULHWCH AND OLWEN, but he is best seen in THE LADY OF THE FOUNTAIN, where he appears as the guardian of the beasts of the forest. He is a black giant with a club, who beats upon the belly of a stag in order to call the beasts together. Traces of this archetype are perceivable in the earlier texts about Merlin, who is shown in the VITA MERLINI as riding on a stag. His function is the guardian of the totemic forces inhabiting the land; as genius of the primal forest and instructor in wisdom he presents a threatening but enlightening challenge to the questor.
The Tower - ע - Bala Lake
Bala Lake (Llyn Tegid in Welsh, meaning Lake of Serenity) was the largest natural body of water in Wales prior to the level being raised to help support the flow of the Llangollen Canal. It is 4 miles / 6.4 km long by a mile / 1.6 km wide) and is subject to sudden and dangerous floods. It is crossed by the River Dee and its waters are famously deep and clear. The town of Bala sits at its northern end and the narrow gauge Bala Lake Railway runs for several kilometres along the lake's southern shore.
Bala Lake has abundant pike, European perch, trout, eel and gwyniad. It also contains the very rare mollusc Myxas glutinosa - the Glutinous snail. According to legend the lake is inhabited by a monster known affectionately as Teggie.
The Star - פ - Branwen
Branwen, Daughter of Llyr is a major character in the Second Branch of the Mabinogi, which is sometimes called the Mabinogi of Branwen after her. Branwen is a daughter of Llyr and Penarddun and has been interpreted as a goddess of love and beauty. She is married to the King of Ireland, but the marriage does not bring peace.
Branwen, whose name means "white raven" in Welsh, is the Welsh goddess of Love and Beauty. She is considered the Venus of the Northern Seas and is also worshipped in Manx. She is one of the five Goddesses of Avalon and is considered one of the three matriarchs of Britain (along with Rhiannon and Cerridwen) The Full Moon in June is Branwen's Moon. She also is honored during the waxing moon of each month. She is associated with the Goddesses Artemis (Diana), Eriu, Nymph, and Aphrodite (Venus). She is considered to be a Maiden aspect of the Goddess although she has many Mother attributes. The magical attributes associated with her include invoking beginnings, new projects, ideas, inspiration, energy, vitality, and freedom.
The Moon - צ - Lake Of Maidens (Llyn y Morwynion)
Lake of the Maidens, where the serving maids of Blodeuwedd fell while being pursued by Gwydion.
The Sun - ק - Llew Llaw Gyffes
In Welsh mythology, Lleu Llaw Gyffes (/ɬeɨ ɬau gəfes/, sometimes mispelled Llew Llaw Gyffes) is a character appearing in the fourth of the Four Branches of the Mabinogi, the tale of Math fab Mathonwy. Lleu (sometimes mispelled Llew) is widely understood to be the Welsh equivalent of the Irish Lugh and the Gaulish Lugus.
The name Lleu shares the same roots as the Modern Welsh words golau ("light"} and lleuad ("moon"), and means both "light" and "bright". Like the word golau it can also refer to fair or blond hair.
Judgment - ר - The Sleepers
The Brenin Llwyd (Welsh for "Grey King") is a being believed by some to inhabit the mountains of Snowdonia in Wales. Reports of its appearance vary. It is sometimes described merely as a "presence", but it has also been reported to be large, hairy, man-like creature,  similar to the American bigfoot or the Himalayan yeti.
Susan Cooper's novel The Grey King, the fourth book in The Dark is Rising series, is named for the Brenin Llwyd. In the book, he is a lord of the Dark, who is an ever-present, oppressive force pervading the area around Cadair Idris. His agents are the milgwn, spectral foxes who seek to prevent Will Stanton and Bran Davies from awakening the Sleepers who will ride against the Grey King and the forces of the Dark.
The Universe - ש - Cadair Idris
Cadair Idris or Cader Idris is a mountain in Snowdonia, north Wales. It lies at the southern end of Snowdonia National Park and reaches 893 m at its summit, named Penygadair (Welsh for "top of the chair").
Cadair Idris means "the chair of Idris" in Welsh, a reference to a giant in Welsh mythology and the resemblance of one of the mountain's cwms, Cwm Cau, to an enormous armchair. The spelling Cader Idris is often found in both Welsh and English, as reflected in the name of the local secondary school, Ysgol y Gader (never Ysgol y Gadair). This spelling is presumably due to the common pronunciation in everday speech of the Welsh word cadair as [kader] (rather than [kadair]). However, Cadair Idris is the form used on modern maps and many people regard Cader as incorrect.
Cadair Idris is imbued with numerous legends; some nearby lakes are supposed to be bottomless, and anyone who sleeps on its slopes will supposedly awaken either a madman or a poet.
As mentioned above, the mountain's name refers to the giant Idris of Welsh mythology. The name is sometimes translated as Arthur's Seat.
The Fool - ת - Peredur
Peredur is the name of a number of men from the boundaries of history and legend that was Dark Age Britain. The most well known of them appear in the following literary sources:
Peredur ab Efrawg (Peredur son of York) - one of the Arthurian Welsh Romances associated with the Mabinogion. It tells the life-story of its titular character. The French author, Chrétien de Troyes transformed him into Percival.
Vita Merlini (Life of Merlin), by Geoffrey of Monmouth – a Peredur, King of Gwynedd, appears in battle, apparently at Arfderydd.
Both may possibly be identifiable as an historical Brythonic king of somewhere in Northern Britain recorded in:
Trioedd Ynis Prydein (The Welsh Triads) – which say he fought at the Battle of Arfderydd; was, with Gwrgi and Arddun, one of triplets born to the wife of Eliffer Gosgorddfawr; died, alongside Gwrgi, fighting the Northern Angle, ‘Eda Glinfawr’.