Twine, interactive fiction tool
http://twinery.org/ (Links to an external site.)
Choice of, interactive fiction tool with RPG elements
https://www.choiceofgames.com/ (Links to an external site.)
BoardGameGeek’s list of helpful software for making card games
https://boardgamegeek.com/thread/991506/resources-card-game-makers (Links to an external site.)
BoardGameGeek’s list of general resources for board games, with some book recommendations
https://boardgamegeek.com/thread/933849/designers-resources-list (Links to an external site.)
RPG Maker, non-free software to make old-school JRPGs (trial software available, and pretty robust)
http://www.rpgmakerweb.com/ (Links to an external site.)
GameMaker: Studio
http://www.yoyogames.com/gamemaker (Links to an external site.)
A friend pointed this out to me: a relatively simple drag & drop game-making tool with a free download. A number of successful indie games were launched with this software.
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