Invision - Prototyping and collaboration for design teams
Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
Proto.io - Create fully-interactive high-fidelity prototypes in minutes that look and work exactly like your app should. Sign up for a free 15-day trial and get started.
Free Countdown Timer - Free Countdown Timer is a free, full-featured and user-friendly countdown timer for Windows
Balsamiq - Balsamiq. Rapid, effective and fun wireframing software.
SnapTimer - SnapTimer is a simple, free, portable countdown timer for Windows.