Alexa Skill Kit - Effortless Alexa Skill development with AWS Lambda
SmallDevTools - Handy developer tools with a delightful interface
BotTalk - Create Alexa skills and Google Assistant actions with Markup
LaunchKit - Open Source - A popular suite of developer tools, now 100% open source.
OK Google - Explore over 150 Google Now voice commands in one place
Profitable developer tools database - A database of 103+ hand-curated profitable developer tools