For those of us who like drawing your apps/ui by hand on paper instead of a on OnmiGraffle, or Microsoft Visio, or LibreOffice Draw. I personally find drawing by drag-drop a chore, I just keep these on a folder on my desk. Available in 4:3 (eg iPads, android devices), 3:2 (iPhone 4S and earlier, many android devices), 16:10 (mostly android tablets), 17:10 (Galaxy Tab 7, Kindle Fire), and 16:9 (iPhone 5 & 6, HDTVs), on US Letter Size; one per-sheet, and four per-sheet.
Also great for sketching unexpected, middle-of-the-night ideas; or for story-boarding.
- [Google Drive] Paper Stencils