Michael Machalko’s Thinkertoys is a great catalog of brainstorming techniques. If your idea of brainstorming is “sit down with a blank sheet of paper and list things,” definitely check it out! The examples are all business-focused, but there’s one technique, the Idea Box, that I’ve found especially helpful for game design challenges.
The core of the idea box is to break your problem up into a few components, generate ideas for each, and combine them in an explosion of possibilities. Start by writing down a few categories–five or six is usually good–as column headers. Then come up with several concepts or associations for each, writing them under the headers. Think of at least five each, more is better. Then take one item from each column and combine them. I like to roll dice or use Inspiration Pad Pro to generate prompts.
For Game Chef 2016, my categories were Technology as a Theme, Use of Technology, and the four ingredients: Alarm, Dance, Sketch, and Sunlight. This produced combinations like “Anonymity, music playlist, waking up, clubbing, sketch comedy, and bright” or “Intellectual Property, spam, heists, manners, inspiration, and bleach”. Draw Fortress came out of “Security, Wiki (revise and add to what has been written), fire, ballet, pens, and the Sun.” I wound up dropping ballet and the Sun when I couldn’t make them fit, and transplanting the “revise and add” aspect onto paper.
For the Nontraditional Fantasy RPG Design Challenge, there were criteria about settings and about rules, both phrased as “Must not include X.” I found it hard to brainstorm in the negative. So I came up with a list of themes and settings that would easily meet the setting criteria, and a list of mechanics that would meet the rules criteria, and started mashing them together. Midnight at the Library of Worlds came from Bookbinding + Night-time Animals Save the World.
My full lists:
Modern day with magic
Small town life
Fairy tales in modern-ish day (post 1900s)
Some other myths in modern-ish day (post 1900s)
Baby gods learning to control their domains
Fantastical Colonial Philippines
Painting, drawing, other art
Rebellion against an evil government
Ancient Rome and Greece
Do Pilgrims of the Flying Temple
Drawing stones or tokens
Rock paper scissors
Night-time Animals Save the World
Something like NTASW, but with dice
Die pool where successes buy effects
Simultaneous blind bidding
Draw cards instead of rolling dice
Spend finite resource
Throw yarrow stalks
Second price auction