In 1981, LEGO released 8 Duplo sets in the subtheme Building Sets, all of these sets have been retired.
Most valuable 1981 LEGO Duplo set
2360 Basic Set $108.01
Highest growth 1981 Duplo set
2621-2 Tractor +2832.94%
Largest 1981 LEGO Duplo set
2370 Basic Set 45 pieces
Most owned 1981 Duplo set
2350 Basic Building Set
Theme Duplo
Year 1981
Pieces / Duplo figures 9 / 1
Availability Retired
2330 LEGO Duplo Basic Set
Theme Duplo
Year 1981
Pieces / Duplo figures 17 / 1
Availability Retired
2340 LEGO Duplo Basic Set
Value $35.16
Theme / Subtheme Duplo / Building Sets
Year 1981
Pieces / Duplo figures 22 / 2
Availability Retired
2350 LEGO Duplo Basic Building Set
Retail $14.99
Value $87.03
Growth  +480.6%
Annual growth 4.2%
Theme Duplo
Year 1981
Pieces / Duplo figures 32 / 3
Availability Retired
2360 LEGO Duplo Basic Set
Value $108.01
Theme Duplo
Year 1981
Pieces / Duplo figures 45 / 4
Availability Retired
2370 LEGO Duplo Basic Set
Retail $12.95
Theme Duplo
Year 1981
Pieces / Duplo figures 2 / 1
Availability Retired
2621-2 LEGO Duplo Tractor
Retail $1.70
Value $49.86
Growth  +2832.9%
Annual growth 8.2%
Theme Duplo
Year 1981
Pieces / Duplo figures 2 / 1
Availability Retired
2624 LEGO Duplo Helicopter
Value $68.10
Theme Duplo
Year 1981
Pieces / Duplo figures 14 / 2
Availability Retired
2644 LEGO Duplo Service Station
Value $92.74