As a tabletop game designer, artist, writer, and publisher, I gotta say that Notepad as a digital tool on smartphones and laptops is one of the tools I use a LOT. also physical notepads, too. Libre Office: Libre Office Writer and Libre Officer Calc, are also very often used. 3D Paint is one of those tools that I happen to use regularly, because it is easy to use, available almost everywhere, and you can use it on the net, too. I list these because I use these all regularly among other tools, programs, etc., but I also like these. Simple free tools that are usually already even on library computers. I like to keep my easy, simple and carefree.
And I shall mention these, too.
I have used Rupert Spore’s Fictional Area Creation Tool ( https://rupert-spore.itch.io/fictional-area-creation-tool-fact ) as a writing prompt tool and as an inspiration sparkler.
I've also used Creature Feature All Dice Table by Jesse Galena and Thomas George as an inspiration ignition as part of my creative writing process. You can get yourself the latest copy of it (https://rexiconjesse.itch.io/creature-feature) on their creator page ( https://rexiconjesse.itch.io/ )