Sadly the Holiday celebrations that we know of in the Germanic world seem always be written about from the Christian perspective looking backwards, and on top of that the sources are usually pretty skimpy on details. Making it perfectly in line with exactly everything else we know about pre-conversion societies.

One possible Anglo-Saxon heathen celebration is mentioned by Bede, and he names it "Modranicht" (mother's night). Interestingly he places its celebration on the 8th calends of January and on the same night that Christ's birth is celebrated (that's what it says in the Latin, not sure how calends and all that line up to the modern calendar). He doesn't provide any details on what these celebrations entailed, because why would he do that?!

Then there's the famous Yule celebrations that variously get attributed to the broader Norse, Scandinavian, and Germanic worlds. There's linguistic evidence that the name (as a month) was at least somewhat widespread among various Germanic groups, such as the Goths and the Anglo-Saxons, in addition to the Norse.

The sagas, with all the caveats that need to be attached, mention that these celebrations often heavily involved sacrifice and what we might call a "fair", along with the heavy imbibing of ale and mead.

The Saga of Haakon the Good claims that he moved the traditional Yule celebrations to correspond with the Christian celebrations around Dec. 25th. It also claims that the celebrations were supposed to go on for as long as the ale and food lasted, which seems a much better system to my eyes.

The Herverar Saga says that the daughter of an elf king was abducted in the middle of these proceedings. She was placing blood on an altar when she was abducted by the infamous Skargad. She was later rescued by Thor. Some scholars have taken this to mean that these celebrations were presided over by women/priestesses, but this is coming under a lot of scrutiny these days.