GSS is a JavaScript layout engine based on Grid Style Sheets (constraint CSS) using Cassowary constraint solver. It enables declarative relational layouts—expressing 'item A aligned to the right of item B'—and compiles these constraints into standard styles at runtime or build-time. Though experimental and labeled unstable, it showcases advanced layout paradigms beyond traditional CSS.
MiG Layout is the most versatile and flexible Java Swing and SWT Layout Manager. MiG Layout can produce flowing, grid based, absolute (with links), grouped and docking layouts and you will never have to switch to another layout manager ever again!
libwt is a SDL based c++ toolkit that provides signal & slots and a layout manager. It utilizes, when possible, the SDL framework like SDL_Mixer, SDL_Image, SDL_ttf, SDL_gfx, SDL_net etc.
EasyLayout is flexible and easy to use grid based LayoutManager. EasyLayout is designed for making form design easier and quicker without need of fancy drag and drop form painters.