Lumos – Snow Winter Powerpoint Templates
https://elements.envato.com/lumos-snow-winter-powerpoint-templates-QC2DS2V
Free 
Merryful – Christmas Powerpoint Template
https://elements.envato.com/merryful-christmas-powerpoint-template-VXDGWEU
Free 
Nexyear – New Year Powerpoint Template
https://elements.envato.com/nexyear-new-year-powerpoint-template-2R9SRBF
Free