Tiled extensions for RSDK map formats, with projects for Sonic games.
Simply take the tiled folder for the game you want to edit and place it in the same folder as an extracted Data.rsdk (not inside the Data folder itself), then open the .tiled-project file in Tiled.
As Tiled cannot read the GameConfig.bin to get the level list, I have created a set of files for each level and chunk set. The .scn files are JSON files that can be edited in any text editor, and contain the stage folder and scene ID for the level; the .cnk files are plain text files that contain only the stage folder name. Currently, the addon will only work if the 16x16Tiles.gif, 128x128Tiles.bin, Backgrounds.bin, and scene file all exist within the same folder (TileConfig.bin and StageConfig.bin cannot be edited). Support for a fallback folder may be possible in the future to better support mods.