There seems to be no Type1 font for use with pdftex. But with LuaTeX or XeTeX you can try out the TrueType font “Proofreader”, that provides proofmarks used in German Language. It can be downloaded in a ZIP file from http://www.maxfonts.com/fonts/p/proofreader.font (the link to the original vendor is dead) and used for free (the license is CC BY-ND 3.0). As you are a German, you can read the included PDF file. (For all: The mapping is shown in this file. It should be also recognizable, if you don’t understand German, search for “Tastenbelegung”.) In my humble opinion the “deleatur” sign is ugly, the “kursiv“ line is angular instead of wavy.
I think it would be the best to create a new fontfamily (means: use
fontspec) and an own speaking command for every proofmark, because the mapping to the letters looks like it was done at random.
A very different and perhaps much better approach may be to draw all proofmarks with TikZ or something similar and assign them to own (speaking) commands.
Update: Though they are not TeX related, I want to add some links: PDF Editing – Making the Most of the Stamps Tool and Free Stamp Collections for PDF-XChange Viewer. At least the marks dedicated for PDF-XChange Viewer are embedded in PDF files and could therefore used in other ways.