Found that there were a few episodes of Arrow, one Supergirl, and a couple of episodes of Legends that all had some Christmas celebrating in some form. 
Also, the Beebo the God of War episode of Legends celebrated Hanukkah as well as Christmas. 
If I find any others, or something different to also add I’ll let you know @Reaganfan78. 
Thank you for hosting this as it has been a lot of fun seeing what is out there. 