If I could have had a #4, this would have been it. 
Martin Mull’s “Santafly” – that takes me back! Great pick!
My suggestion is “Just for Now” by Imogen Heap.
I’m working on a cover of “Auld Lang Syne” right now. We can add that if I manage to get it out the door on-time. 
The Angels Cried - Alan Jackson
Christmas in Killarney - Bing Crosby
Let It Be Christmas - Alan Jackson
Mele Kalikimaka - Bing Crosby & The Andrew Sisters
A’ Soalin’ - Peter, Paul & Mary
Christmas Is A-Comin’ - Bing Crosby
Which 3 of these do you want on the list?
I’d like to add an honorable mention:
Winter - The Mellomen (featuring Thurl Ravenscroft) backed by Spike Jones and his City Slickers. On Spotify but they only display Spike Jones.
Over three hours of music now. Has anyone here listened to it yet besides me?
Not yet - waiting for 1) it to fill up a bit more, and 2) December.
How about Straight No Chaser’s “Text Me Merry Christmas”? It’s on Spotify.
I’ll come back later when I decide on two more - this is kind of hard!
For the list: “Christmas in Prison” - John Prine
It was Christmas in prison, and the food was real good
We had turkey, and pistols carved out of wood.
Here’s two more:
“Christmas in Hollis” by Run DMC
“Old City Bar” by the Trans-Siberian Orchestra
“Alone on Christmas” by Quiet Company
“White Wine in the Sun” by Tim Minchin
“What Christmas Means to Me” by Quiet Company
Honorable Mention: “Merry Christmas, The President is Terrible” by Quiet Company. It’s from 2019, so I’m amused by the optimism of lyrics “It’s been a bad year, but it’s over now.”
I thought we already had that on the list, but his is what @Lancia wanted
White Wine in the Sun, Kate Miller-Heidke (not the Tim Minchin version. Puke)
Aimee Mann - “Calling on Mary”
(other choices were already picked so just that for now)
There’s a cover by Sonic Youth. That was going to to be one of my suggestions, anyway.
"Merry Christmas from the Family - Robert Earl Keen
Hard to choose!
Let It Be Christmas
Christmas in Killarney
Christmas Is A-Comin
The rest will have to be honorable mention.
The Cherry Tree Carol by Inner Voices (feat. Al Jarreau)
Caroling, Caroling by the Singers Unlimited
Deck Us All With Boston Charlie by Lambert, Hendricks, and Ross
Just so we’re clear, is this going to be an actual playlist, such that if I sign up for Spotify, I can search for it and listen to it?
It’s already there. See the link in the OP.
I was going to recommend some Mitch Benn but most of his best Christmas songs aren’t on Spotify (although you can listen to “Christmas Single” - yes, that’s the name of it).
By what singers?