Text Editors & IDE of choice for everyday usage

Full-featured, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites.

HackMD is a browser-based, real-time collaborative markdown editor. It was inspired by hackpad but focuses more on speed and flexibility.
Features:
Collaboration
PDF, Image, and Video Embedding
Auto-Save and Revision History
Markdown Extensions (TeX, Flowcharts, Emoji, Graphviz, ...)
Book Mode
Presentation Mode (with Themes and Animations)
Easy (Shared) Notetaking via Book Mode
Disqus Integration
and more

Vim ("Vi IMproved") is an advanced text editor that allows syntax highlighting, word completion and has a huge amount of contributed content. It also has a GUI version called GVim.

VS Code is more than just a code editor, it provides the tools and extensions to compile, debug, compare, refactor, and even manage code repositories all within a highly-customised development environment.

IntelliJ IDEA is an integrated development environment (IDE) written in Java for developing computer software. It is developed by JetBrains, and is available as an Apache 2 Licensed community edition, and in a proprietary commercial edition.