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.
KanbanMail - A Kanban board for your emails.
WorkPatterns - The modern manager's toolkit: 1:1s, feedback, & recognition
Sunsama - Calendar and scheduling for teams
SlimPlanner - Team scheduling, resource planning, task management
Delibr - Delibr is an end-to-end tool for product management to structure, collaborate, keep track of questions, capture decisions and conversations.