Sprite Fusion
6.9#4 in game level editors$14.99, paid onceFree planWebLinuxmacOSWindows
VisitSprite Fusion suits people making 2D game maps, retro-style games, virtual tabletop maps, or educational apps. The free browser edition may fit smaller maps, while the desktop edition is an option for offline work and larger exports.
It suits people making maps for Doom-family games, especially those using ZDoom-family ports. Linux users should be prepared for experimental support.