Your search for "(corrugated) cardboard" revealed the following:

Corrugated board (deck plate) 2.0 x 1.0 x 150 x 300 mm : Evergreen plastic material, non-scale 4528

Corrugated board (deck plate) 1.5 x 1.0 x 150 x 300 mm : Evergreen plastic material, non-scale 4527

Paper corrugated board [pitch approx. 0.7 mm] 200 x 19 mm, 5 sheets: Northeastern Material HO(1:87) 40100

Corrugated board 2.4 x 1.6 x 76 x 279 mm, 2 pieces : Northeastern Wood, non-scale 6021

Corrugated board 3.2 x 1.6 x 76 x 279 mm, 2 pieces : Northeastern Wood, non-scale 6022

Corrugated corrugated siding, 2 ply: PLASTRACT PLASTIC 1:16 PS-27

Corrugated corrugated siding, 2 ply: PLASTRACT PLASTIC 1:24 PS-26

Roofing Corrugated Board : Grant Line Unpainted Kit (Parts) HO (1:87) 5218

Loading cardboard (large) : YSK Unpainted kit N (1:150) Part No. 470

Loading cardboard (small) : YSK unpainted kit N (1:150) Part No. 469

Cardboard box (loose) : YSK Unpainted kit N (1:150) Part No. 471

Corrugated sheet 1.0 x 1.0 x 88 x 609 mm, 2 pieces : Northeastern wood, non-scale 70424

Corrugated sheet 2.4 x 1.2 x 88 x 609 mm, 2 pieces : Northeastern wood, non-scale 70436

Corrugated sheet 1.6 x 1.6 x 76 x 279 mm, 2 pieces : Northeastern Wood, non-scale 6020

Corrugated sheet 1.6 x 1.0 x 88 x 609 mm, 2 pieces : Northeastern wood, non-scale 70426

Wooden pallet (large) light brown : YSK Unpainted kit N(1:150) Part No.461

Wooden pallet (small) light brown : YSK Unpainted kit N(1:150) Part No.463

Wooden pallet (small) brown : YSK Unpainted kit N(1:150) Part No.464

Plastic pallet (blue) : YSK Unpainted kit N (1:150) Part No. 465

Plastic pallet (gray) : YSK Unpainted kit N (1:150) Part No. 468