Your search for "Diagonal box" revealed the following:

Hexagon bolt: nut 1.0mm flat diameter : Sakatsuo Detail up Non-scale 4501

Hexagonal pipe joint, double flat 1.5mm : Sakatsu Detail Up Non-scale 4452

Hexagon bolt: nut flat diameter 1.0mm (brass) : Sakatsu Detail up Non-scale 4504

Hexagonal bolt: nut 0.8mm flat diameter : Sakatsuo Detailing Non-scale 4491

Square bar 1.5 x 3.2 x 350 mm : Evergreen Plastic material, Non-Scale 156

Miniatuart mini Christmas ver. [Father Christmas] : Sankei Kit Non-scale MP05-13

N Gauge Mini Layout [Railway in Brilliant Autumn Colors]: KDF Pre-Painted Finished Model 1/150 scale

Spongebob Material [Clamp for Ridge] Autumn Mix (Autumn Leaves) [Large Bag] : Woodland Material - Non-scale FC186

Athlete Doll Boxing Down A: Sakatsuo 3D printed finished product HO(1:87) 220

Stone material Crushable stone square (1.0-3.0mm) : Morin material Non-scale CR-01

Hexagon joint, flat diameter 0.6mm (for 0.25mm wire) : Sakatsuu Detail Up Non-scale 4470

Coin-operated Play Equipment A : Baioudou Pre-colored finished product, HO (1:83) scale, AC-069-83C

Deliverer and his luggage : Preiser - Painted Complete Z (1:220) 88511

Self-propelled miniature train with built-in battery Pole Specifications: Yoshiaki Ishikawa Finished product N (1:150)

Powdery Substrate Country Glass (3) Light Green : Moline Materials Non-scale CS-03

Nickel silver round wire 0.6mm : Sakatsu Material Non-scale 4605

Nickel silver round wire 1.2mm : Sakatsu Material Non-scale 4610

[Model] Ramp (Rental Warehouse, etc.) Note: Equivalent to Kobaru: Sakatsu Unpainted Kit N (1:150) 3815