if you want to find out which casinos are having Christmas bonuses/promotions try checking the gambling site's ANN thread here in the forum, they usually post if they are having Christmas bonuses/promotions. also, I remember reading on crypto.games ANN thread that they are having daily challenges and giveaways as part of this month's Christmas bonuses/promotions.
That's true, the announcement discussion thread of all the available gambling platforms available on this forum could also be put into consideration, but I must make this in addition that OP should try as much as possible in reading through the conditions that comprise some of these offers before applying, bonus sometimes is nothing free because you will have to work your way out for it before being eligible.
Exactly because bonuses usually come with strong terms and conditions which make it almost impossible to profit from them, and sometimes, due to that condition, many gamblers do not want to get involved with bonuses and will prefer to just deposit and play their own money.
But since Christmas is something that is widely celebrated and a lot of holidays are planned around that time, it becomes good for some casinos to give their clients a condition-free bonus as a gift for the season.