In my husband's Wood family, the tradition was for first cousins to send each other greeting postcards for major holidays.
This Christmas card was sent to my husband's "Uncle Wally" (Wallis Walter Wood), in the 1910s, from first cousin Chester Maxwell Carsten (1910-1967) in Toledo. No postmark, so this was probably mailed with a bundle of cards to the Wood cousins in Cleveland.
My family's holiday traditions were different. Here's a b/w photo of my Mahler/Burk cousins at a Hanukkah party we all attended in the late 1950s. Note the desserts and chocolate milk for kids!
Also, a surprising number of my ancestors and relatives were married on Christmas Eve (including at least one of my 2d cousins). My previous post mentioned my great-uncle Alex Farkas marrying Jenny Katz on Christmas Eve, and here's the only photo I have of that wedding. Alex was my grandma's older brother.
As identified in the photo, my grandma Minnie Farkas Schwartz is at right, with long dark hair. Her husband Ted Schwartz is next to her, wearing a funny hat. In front of them is their young son, Fred. Mom and her twin weren't even a gleam in their eyes--yet.
Wishing you all the happiest and healthiest of holidays! Celebrate with your family's traditions.