IntelliJ IDEA & IntelliJ Platform
Launch an external diff tool like WinMerge in Eclipse
Eclipse plugin for VCS ClearCase
EditBox is the Eclipse plugin for source code background highlighting.
Programming in MS Paint
Vim-like editing in Eclipse
ZKCC is a netbeans java code completion plugin for zul files.
Paste from your Copy history!
Jxt4RunPlusJ is a source code editor and creator.