Here is my list of various sources for exotic or highly specialized materials:

Textiles:

• tacticaltrim.de // Cordura, various textiles to military standards
• extremtextil.de // Kevlar fabric, Kevlar thread, Cordura, Nomex, Aramid
• kanirope.de // Kevlar rope

Metals:

• lenzshop.de // Copper (profiles and plates)
• tp-maier.de // Bearing bronze as round material, also carries PTFE/Teflon plates
• schmiedeglut.de // Grade 5 titanium, small quantities, sheet
• schanz-shop.de // Grade 5 titanium, small quantities, sheet
• titanwerk.de // Titanium, large quantities, various semi-finished products (sheet, plates, round material, profiles, nuts, bolts) various qualities

Electronics:

• octamex.de // Solder masks for lamination
• tridelta-weichferrite.de // Soft ferrites, various core shapes and rings