A free program for Android, by Adobe.

Adobe Comp lets you design and layout an idea in the form of a layout template. You can use real assets like photos, text, shapes, and fonts to build the template and send it to Photoshop, Illustrator, or InDesign for additional design refinement.

Comp allows you to explore an idea using different design elements. You can also take advantage of Adobe Stock, which provides royalty-free images.

Adobe Comp works seamlessly with Photoshop, Illustrator, InDesign, and Fresco to explore an idea, and you can also use Libraries to access your assets anytime such as color themes and stock images