The custom of naming this aett after Freyr, the Vanir god of fertility and prosperity, a fitting patron given the group's opening rune Fehu, cattle and movable wealth, is widespread in modern rune literature and practice, yet it is not a naming this entry can trace to the Poetic Edda, the Prose Edda, or to either surviving rune poem, the Old English or the later Norwegian and Icelandic verses that name and gloss the individual runes but say nothing about naming the three aettir after specific gods at all.
The Kylver Stone and the other early runic evidence establish the grouping into three eights beyond doubt; they do not name the groups after deities, and the god based naming scheme now common in books and courses on the runes appears to be a later interpretive layer added by twentieth century rune workers rather than an inheritance from the medieval sources themselves. This entry states the naming plainly because it is the convention the reader will meet everywhere else, but honesty about a modern tradition requires saying clearly what belongs to the archaeological record, the eight runes and their attested grouping, and what belongs to a more recent, unattested overlay, the specific choice of Freyr as this group's patron. Michael Barnes' handbook on runes likewise treats the god naming of the aettir as outside the run of primary evidence the discipline of runology otherwise works from.
Sources Runes: A HandbookMichael P. Barnes with An Introduction to English RunesR. I. Page