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 $188, a growth of 573%.
Most valuable 2015 LEGO Seasonal Christmas set
40139 Gingerbread House $65.95
Highest growth 2015 Seasonal Christmas set
40125 Santa's Visit +233.53%
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 $16.61
Growth  +66.3%
Annual growth 3.8%

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 $33.32
Growth  +233.5%
Annual growth 7.2%

40138 Christmas Train

Theme / Subtheme Seasonal / Christmas
Year 2015
Pieces 233
Availability Retired
40138 LEGO Christmas Train
promotional
Value $45.71
Annual growth 3.4%

40139 Gingerbread House

Theme / Subtheme Seasonal / Christmas
Year 2015
Pieces 277
Availability Retired
40139 LEGO Christmas Gingerbread House
promotional
Value $65.95
Annual growth 7.2%

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 $14.99
Growth  +87.6%
Annual growth 4.5%

5003083 Christmas Ornament

Theme / Subtheme Seasonal / Christmas
Year 2015
Pieces 32
Availability Retired
5003083 LEGO Christmas Ornament
promotional
Value $11.56
Annual growth 5.4%