Editors
Cave Story Editors
Dog Studio
by Sam & K
A fork of Booster's Lab with theme support and a multitude of new features. Requires Java 17 or higher.
Dog Studio v2.0
Github Sky Dragon Editor
by Jakzie
Still in development, but stable enough to create mods with, and contains a variety of QoL features such as the ability to export maps as an image and a more CE-like UI.
Sky Dragon Editor v0.0.15
Github Page Booster's Lab
by Noxid
A Java-based editor that was the de facto Cave Story editor for many years. It's no longer updated.
Booster's Lab v0.5.1.1 (English)
Booster's Lab v0.5.1.1 packaged with JRE (English)
Booster's Lab v0.3.3.0 (Japanese)
Forum Thread Github Cave Editor
by Wistil
No longer updated and missing some features compared to Booster's Lab such as the ability to apply ASM/hex patches or edit CS+/CSE2/D-RS/etc, but its UI is preferable to some people.
Cave Editor v0.99d
Source Code
Forum Thread The King's Table
by Brayconn
Not recommended for beginners, but if you know what you're doing it can be used to mod most of the official console ports. The Avalonia (new) version was never finished, so it is best to stick with the WinForms (old) version for now.
WinForms version (more features)
Avalonia version (faster ui, less features)A more in-depth comparison table can be found here if needs be.