You mean like a map editor? Are you talking 2d or 3d? For 2d, I like Tiled. Source: over 1 year ago

Responsibilities Understand and design for the psychology of the player experience at all times. Design and iterate all game mechanics, including unique selling points as well as familiar game play. Use a google docs spreadsheet to manage the game design. Help create a storyline and help choose a compelling theme for the game. Create level designs using Tiled (http://mapeditor.org/). Design around 500 rooms with... Source: almost 2 years ago

I'm not good in programing and I'm about to develop a story driven action rpg style game. I like to be able to do a lot (sometimes turn-based, sometimes hack'n'slash), use different weapons, be able to develop the character's level, weapons... And to have access to lots of assets and tools that make development easier (e.g. Rpg maker works with tiles mapeditor.org). thoughts? Source: about 2 years ago

You could easily do this without having to implement anything. Have people download Tiled at mapeditor.org and make their maps with it, then they can export their maps to .json and you could open them on your machine for review with the same program. Source: about 2 years ago

The free tileset editor I used is called Tiled and can be downloaded here: mapeditor.org. Source: about 3 years ago

If you're looking for an icon editor, there are many available, such as IconWorkshop, Icofx, and Iconion, but I haven't tried any of those. Source: 12 months ago