Yngvi
Old Norse Yngvi, Old High German Inguin and Old English Ingwine are names that relate to a theonym which appears to have been the older name for the god Freyr. Proto-Germanic *Ingwaz was the legendary ancestor of the Ingaevones, or more accurately Ingvaeones, and is also the reconstructed name of the Elder Futhark ŋ rune.
A torc, the so-called "Ring of Pietroassa", part of a late third to fourth century Gothic hoard discovered in Romania, is inscribed in much-damaged runes, one reading of which is gutanī [i(ng)]wi[n] hailag "to Ingwi[n] of the Goths holy".
Etymology
Old Norse Yngvi as well as Old High German Inguin and Old English Ingwine are all derived from the Proto-Germanic *Ingwaz. Sound changes in late-Proto-Germanic transformed *Ingwaz into *Ingwi(z) in the nominative and *Ingwin in the accusative. That his epithet *Fraujaz appears in Old Norse compounds Ingvifreyr and Ingunarfreyr, as well as in Old English fréa inguina, both of which mean 'Lord of the Inguins', i. e. the god Freyr, strongly indicates that the two deities are either the same or were syncretized at some very early period in the Germanic migration (or possibly before). The Ingvaeones, who occupied a territory roughly equivalent to modern Denmark, Frisia and the Low Countries at the turn of the millennium, were mentioned by Pliny the Elder in his Natural Histories as one of "five Germanic tribes". Pliny asserts their descent from *Ingwaz, perhaps himself the son of *Mannus, the Proto-Germanic 'first man'. Other names that retain the theonym are Inguiomerus or Ingemar and Yngling, the name of an old Scandinavian dynasty.