Icons should be embedded with .rc and .dproj files. Binary resource files are awkward and confusing. I'd say it is a bad style to put them into version control.

You have to extract icon from resource if it is not stored elsewhere. If it is stored then .res file is duplicating. And what about all those .res file with default Delphi icon? A dozen of dll-projects for example?

I wish this line be the first one by default to make repositories cleaner... But right you are. Too many people do store .res files and they would lose them in such case.

Perhaps I should create some "recommended" section in this .gitignore with lines commented.