To-Do Lists and Task Management:

1. Todoist:

A popular and user-friendly option, Todoist helps you break down tasks into manageable steps, set priorities, and collaborate with others. Its clean interface and intuitive features make it a breeze to stay organized.

2. Microsoft To Do:

Integrated seamlessly with other Microsoft products like Outlook and Calendar, To Do offers a simple yet effective way to manage your tasks and stay on top of deadlines.

3. TickTick:

This app boasts powerful features like recurring tasks, subtasks, and time estimates, along with a focus mode that minimizes distractions. Its "pomodoro timer" function can help you stay productive in short bursts.

Time Management and Focus:

1. Forest:

Gamify your focus! Forest lets you plant virtual trees that grow as you stay focused on your work. If you get distracted and check your phone, the tree dies. This playful approach can help you stay present and avoid procrastination.

2. Freedom:

This app blocks distracting websites and apps on your devices, creating a distraction-free zone for focused work. You can set custom schedules and whitelists to ensure you can still access essential tools while minimizing temptations.

3. Focus Keeper:

Employ the Pomodoro Technique with Focus Keeper, which sets 25-minute work intervals with short breaks in between. This method can help you maintain concentration and avoid burnout.

Communication and Collaboration:

1. Slack:

A popular communication platform for teams, Slack allows for instant messaging, file sharing, and channel organization. Its integration with other tools like Google Drive and Trello make it a versatile hub for collaboration.

2. Zoom:

While not entirely free, Zoom offers a generous free plan with enough features for small teams or individual use. Its video conferencing, screen sharing, and meeting recording capabilities make it a valuable tool for remote work and collaboration.

3. Trello:

Organize projects and tasks visually with Trello's boards and cards. You can assign tasks, track progress, and collaborate with team members in real-time, making it a great tool for visual learners and project management.

Bonus:

1. Evernote:

This note-taking app lets you capture ideas, organize information, and collaborate with others. Its web clipper saves webpages and articles directly into your Evernote library, making it a handy tool for research and knowledge management.