Alandriel,
"Sun-return", "Sun-awakening" would have been a possibility, the problem is that Yule does not apply to every single culture. IMO "Winter festivity" applies to more cultures, both real and Middle-Earth ones - although, funny enough since the card is supposed to be elven, Elves themselves did not celebrate Yule (or any Winter festivity).
Tolkien did not elaborate much on Elven festivities/festivals, although he was clear about the Eldar not celebrating Yule, or any Winter festival, the Yule-tide being a Shire celebration.
The Company leaves Imladris on Dec. 25th, Yule, and there is no mention of festivity of any kind, but we have references to some kind of mid-winter celebrations both in Arnor and Gondor, which seem to have been slightly different.
The Elves were likely to celebrate Metarë and Yestarë, the Last and First Day of the Elven Year, our Apr. 6th & 7th, but AFAIK, this is not attested.
Based on canon work, IIRC, we only have a couple of references to elven festivals:
A harvest festival (this was, originally, a festival to conmemorate the Coming of the Eldar to Valinor, but Tolkien changed his mind) was held in Valinor. The Valar would clad themselves in raiments in the form of the Children of Ilúvatar, and together with the Eldar would drink and eat, and gather the fruits of the Earth. And upon the Taniquetil an offering to Eru would be made, and there would be song and dance and joy.
The Gates of Summer was a festival held in Gondolin, apparently also linked to the rippening of fruits or harvest. The Gondolindrim would await for the rising of the sun and sing songs, and afterwards, there would be a great feast, and more song and dance.