Players can have snow particle trails if they have a specific item in their inventory. To set the item, hold it in your hand and use
/flurry set. (Works well with custom name/lore items).*
You can use /flurryto give yourself the particle item or /flurry give<player> to give it to another player. (Saves you the time of writing out a whole give command each time for a special item.)
[Permission: flurry.item]
*Server may require a restart for item changes to take effect.
Potential future additions: - Skeletons, Strays, and Witches throw snowballs - Snowball freeze tag
If you have any ideas, please leave them below. HappyHolidays!