What are some of the tools that founder/core team should use during the early days of their startup?

If you initiate your startup, you'll definitely need a robust online planner. I vote for a professional Gantt chart as this tool provides everything for advanced planning and scheduling starting from setting deadlines to setting milestones and dependencies. If you need more information about Gantt chart planning, follow this article https://blog.ganttpro.com/en/ult....

the founder and core team should focus on using tools like Slack for communication, Notion for documentation, Figma for design, GitHub for code management, Trello for task tracking, Google Analytics for website insights, and AWS or Heroku for hosting and development.