Interactive NPS Calculator (by Delighted) - Calculate your NPS easily with this interactive free tool.
TinyNPS - Simple NPS feedback
Jaco - Watch and analyze your users’ behavior
Interactive NPS Benchmarks – Delighted - Enter your score, pick your industry, and compare your NPS
Wootric - Wootric is software that allows apps and websites to take customer satisfaction surveys so that you can properly gauge the popularity and success of your app through the eyes of the people using it. Read more about Wootric.
AppFollow - AppFollow is an integrated solution that makes monitoring, analyzing, and elevating your app's reputation easy.