Q1. If I want to change employer - is it possible to transfer my h1 visa?
Yes, you can transfer your H1B. However, you should not just get stubs without a project and you should move to a project or transfer your H1B immediately.
Q2. If I go for stamping Does it will create any problem?
It may create a problem as you are not in any project, I am not sure in your situation as you have not provided detailed information.
Q3. If I want to file for Green Card- Does it going to create any issues?
This should not cause any issues with the GC process.