I've got tons of this stuff. Are you looking for songs, instrumentals, arrangements???
For Chanukah:
In My Window
Joyous Chanukah
Ocho Candelitas
My dreydl (it would be really fun to do this Klezmer-style)

For Solstice
I have 2 solstice songs by my good friend Alouette Iselin that I sing whenever I'm at a singaround, no matter what the time of year.
The Four Noble Trees by Mark Vyvian-Jones from the book Winter Solstice (with the Green Man on the cover)
Light is Returning

Sheet music, now that's a challenge. Want to pm me your address? I have a few things on Noteworthy Composer, so could email you those. Let me know!