In 2015, LEGO released 6 Seasonal Christmas sets, all of these sets have been retired. For that year, the total price of all retail sets cost $28, today those sets are valued around $191, a growth of 582%.
Most valuable 2015 LEGO Seasonal Christmas set
40139 Gingerbread House $70.00
Highest growth 2015 Seasonal Christmas set
40125 Santa's Visit +206.61%
6 sets

40124 Winter Fun

Theme / Subtheme Seasonal / Christmas
Year 2015
Pieces / Minifigs 107 / 2
Availability Retired
40124 LEGO Christmas Winter Fun
Retail $9.99
Value $17.29
Growth  +73.1%
Annual growth 3.6%

40125 Santa's Visit

Theme / Subtheme Seasonal / Christmas
Year 2015
Pieces / Minifigs 167 / 1
Availability Retired
40125 LEGO Christmas Santa's Visit
Retail $9.99
Value $30.63
Growth  +206.6%
Annual growth 7.0%

40138 Christmas Train

Theme / Subtheme Seasonal / Christmas
Year 2015
Pieces 233
Availability Retired
40138 LEGO Christmas Train
promotional
Value $48.97
Annual growth 3.7%

40139 Gingerbread House

Theme / Subtheme Seasonal / Christmas
Year 2015
Pieces 277
Availability Retired
40139 LEGO Christmas Gingerbread House
promotional
Value $70.00
Annual growth 8.1%

851358 Holiday Bauble White Bricks

Theme / Subtheme Seasonal / Christmas
Year 2015
Pieces 63
Availability Retired
851358 LEGO Christmas Holiday Bauble White Bricks
Retail $7.99
Value $12.77
Growth  +59.8%
Annual growth 4.2%

5003083 Christmas Ornament

Theme / Subtheme Seasonal / Christmas
Year 2015
Pieces 32
Availability Retired
5003083 LEGO Christmas Ornament
promotional
Value $11.13
Annual growth 4.8%