Mikrolo - Free Digital Marketing Strategy Builder!
Watchtower - "Watchtower monitors your competition's websites and alerts you to important changes instantly."
ADYOUNEED - Marketing platform to create and optimize ads
LaunchKit - Open Source - A popular suite of developer tools, now 100% open source.
Keywords Everywhere - Free browser add-on for keyword volume, CPC & competition
Material Design for Bootstrap 4 - Powerful and free UI KIT for the newest Bootstrap 4 and Material Design