GTD

RemNote

The first spaced-repetition powered note-taking tool that lets you structure knowledge exactly in the way you think about it.

Web
Notion

Write, plan, collaborate, and get organized — all in one tool. Write connected notes with rich format and Export to markdown, pdf, etc.

Web Mac Win iOS Android
Quiver

Programmer's notebook, math + Markdown, code snippet.

Mac iOS
Findings App

Your research assistant & lab notebook, all in one app.

Mac
Taskade

Taskade is a beautiful project management tool for both personal use and team collaborations. Taskade ships with task management and note-taking tools.

Web Mac Win Chrome Firefox Android iOS
Todoist

Multi-platform tool to track and analyze tasks.

Web Mac Win iOS Android
Anydo

Anydo comes with a very useful daily review and reminder. Anydo also integrates with its own utilities such as calenders.

Web Mac Android iOS
Evernote

Not so lightweight but still very good for managing life especially since it has got a lot of integrations from a lot of other services.

Web Mac Win Android iOS
Google Keep

Google Keep is light-weight. It comes with powerful search. The App ships with simple drawing and handwriting.

Web Android iOS Chrome
Microsoft To Do

Task management tool backed by Microsoft and works on most platforms.

Web Mac Win Android iOS Chrome
Pomotodo

A mix of todo list and pomodoro timer, with sync across devices and weekly report.

Web Mac Win Android iOS Chrome