Ripley - The project management tool for G Suite
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
SmartSuite - SmartSuite is a collaborative work management platform that enables teams to plan, track and manage workflows, projects and everyday tasks.
Microsoft Planner - Microsoft Planner lets you easily bring together teams, tasks, documents, and conversations for better results.
BambooHR - Personalized HR software for SMBs
CAMPR - Open source project management tool with 16 modules