The Arduino IDE is recommended for beginners, hobbyists, educators, and anyone interested in developing small to medium-sized electronics projects. It's an excellent starting point for those looking to learn about microcontrollers and embedded systems without a steep learning curve.
PlatformIO - Next-generation IDE for IoT
Eclipse - Eclipse is an open source community, whose projects are focused on building an open development platform comprised of extensible frameworks, tools and runtimes for building, deploying and managing software across the lifecycle.
ArduBlock - ArduBlock is a graphical programming language plugin specifically made for Arduino circuits and controllers.
Netbeans - NetBeans IDE 7.0. Develop desktop, mobile and web applications with Java, PHP, C/C++ and more. Runs on Windows, Linux, Mac OS X and Solaris. NetBeans IDE is open-source and free.
Modkit - Modkit is an open-source programming platform that allows programmers with a variety of backgrounds to share their creations and learn from each other and is allowing programmers to make beautiful software.
IntelliJ IDEA - Capable and Ergonomic IDE for JVM