My church sponsors and supports several missionaries, and we keep up with them regularly. The lady who reads the mission reports in church reminds us around the holidays that sometimes this can be a very lonely time for some of them. Some missionaries are involved in such a way with God’s work in their field that they cannot come home to see their families for holidays that they celebrated frequently while in the US. While they may have their immediate family with them, while they might even have new Christians and good friends around them, and while they certainly love God’s work, missionaries can miss their extended families just like we can. (Missionaries Are People, Too)
Consider sending some encouraging words and even encouraging gifts (monetary or otherwise) to missionaries. If the missionary families have children, nice toys are likely to be well appreciated. Check to see what each family needs and wants, and then be sure there’s a way to get it to them in a timely manner. Remember some countries don’t handle mail very well, so you and your missionaries might need come up with a different way to work things out.
Do what you can to encourage missionaries year-round, just remember that there are specific times that can be difficult for them, and not always around holidays.
Related: You Are a Missionary