The English wiki for this tag says only
A maker of signs, mainly for shops and other businesses.
The more extensive entry on the German wiki auto-translates as
The operation of a sign and illuminated advertising manufacturer for the design and production of advertising media and communication systems, such as illuminated and non-illuminated signs, illuminated advertising systems, guidance systems, lettering on facades, shop windows and motor vehicles, as well as lettering for trade fair stands and exhibitions.
I’m looking for a tag for places that make advertising materials: commercial signage, wraps for vehicles, prints on flags or posters etc.
I think this is the most fitting tag, but the English wiki is a bit short, and I’m not sure a native speaker would use it for this kind of business.