Where to find ladders, barrels, and scaffolding/wood walkways as pictured below

Photo from Felix Gaming Pages, this was on display at Warhammer World.

I don’t have a 3D printer but I love these ladders and various other little parts that round out the battle scape. I’m trying to build up an Osgiliath of my own and would love little flavor pieces like this. Does anyone know where to buy stuff like this and ensure it’s in the correct scale? Last part is the most important