For a long time, Google has not updated the "themes" for their forms. We had a very limited selection, but today that all changes!
Google Forms now has 24 new themes to choose from, as well as the option to customize your own theme by choosing a heading and background image.
To choose a theme, click on the usual "Change Theme" button in the toolbar, and you will get a sidebar with new options:
Once you click on "Customize", you get several options:
You can choose an image from your computer for the header and page background, as well as customize font options.
So you can go from old: