If there are hundreds of form and 20-30 projects in the application and during localization the number of .resx files generated will be very high. Is there any way to organize the .resx files and satellite assembly?
If I move the .resx file to common assembly then the design time support for previewing the form is lost.
Is there any standard ways for handling projects with large number form.
I wouldn't recommend that option.
Just switch Localizable to true and handle translations via external tool (not Visual Studio). There are plenty of them, you only need to find the one that suite your needs.
That said, you should only have neutral culture resources in your project. Other languages could be added by compiling translated .resx into satellite assemblies.
Some tools that could be useful: