In 2015, LEGO released 3 Classic Baseplates sets, all of these sets have been retired. For that year, the total price of all retail sets cost $31, today those sets are valued around $67, a growth of 118%.
Most valuable 2015 LEGO Classic Baseplates set
10699 32x32 Sand Baseplate $30.00
Most owned 2015 Classic Baseplates set
10700 32x32 Green Baseplate
3 sets

10699 32x32 Sand Baseplate

Theme / Subtheme Classic / Baseplates
Year 2015
Pieces 1
Availability Retired
10699 LEGO 32x32 Sand Baseplate
Retail $7.99
Value $30.00
Growth  +275.5%
Annual growth 7.6%

10700 32x32 Green Baseplate

Theme / Subtheme Classic / Baseplates
Year 2015
Pieces 1
Availability Retired
10700 LEGO 32x32 Green Baseplate
Retail $7.99
Value $19.42
Growth  +143.1%
Annual growth 11.9%

10701 48x48 Grey Baseplate

Theme / Subtheme Classic / Baseplates
Year 2015
Pieces 1
Availability Retired
10701 LEGO 48x48 Grey Baseplate
Retail $14.99
Value $17.98
Growth  +19.9%
Annual growth 1.8%