Here at Caleb Components we stock DIN 988 Shim Washers, from as small as 3mm x 6mm x 0.1mm.
Carbon steel, plain finish.
Shim Washers are manufactured to precise dimensions and are applied to take up excess gaps in assemblies, (especially bearing assemblies).
Why not check out our full range of Shim Washers using the below link.
https://springfasteners.co.uk/product-category/washers/shimsupport-washers-din-988/