I use Trello. Find just creating a spot for ideas (mine is actually called "random Ideas" and most are awful ideas I'm sure) in whatever tool you already use is the easiest way to get them down somewhere.

I keep two documents:

Projects - for all sorts of stuff that can be anything from little one page apps, t-shirts, art projects, do X but for Y (like do this thing somebody did for US states but for European Countries), slogans to print on beer mugs - whatever.

Serious Projects - anything that will take several months of sustained development to be able to make an MVP and will require funding of some sort.

They're just on google drive, I figure if I get an idea on the bus and it can't last til I get somewhere to enter it in my projects document, it isn't a worthwhile idea.

I’ve been maintaining a simple text file with project ideas for the last 3+ years. It’s accessible from all devices I use. Each idea has a headline and three bullet points describing what it is.

How do you make it accessible from all devices you use?

It’s on Dropbox so I just use whatever apps can access it, specifically I use 1Writer for iOS on mobile.

I use notes and create a new one every time I have a new idea. They are all in a note group "Ideas". Every few months I review it and put it in an excel where I rate it based on joy, roi, time needed, ... and if I feel like it I execute the top rated one.

Absolutely. I come up with a lot of crappy ideas, but there's usually something worth exploring every now and then.

(1) I have an asana project called Ideas. Each task is an idea. I've set up a workflow where I can just send an email to the Asana project inbox and a task gets created. I've kept up this practice for more than a year and I have almost 300 ideas I've logged.

(2) Whenever I think 'alright, I want to work on a new side project', I go through the list of ideas and categorize them. A ton get categorized as trash, and a very small number get categorized as worth moving into customer discovery and validation.

I use Emacs Org mode https://orgmode.org/

Me too. I keep trying different things (notion, bear, Evernote etc etc) and always find myself coming back to emacs.

Yes, I keep a small notebook with me all the time. I jot down small flashes of insights and a-ha moments in it. Then I timely review them. I discard some that doesn't make sense anymore; improve upon the remaining and congregate them in Notion.

Yes. I use google keep for keeping interesting ideas. I also have one card created per month to note down important lessons I learned that month personally and professionally.

I've got a little notebook of things I write down. Had to spend that mandatory college cash on something. It's got a little band to keep it closed and one of those built-in cloth bookmarks.

Yes. I was using a bunch of tools to do so: Google Keep, Simplenote, Trello. Currently switching to Notion.

Google Keep is what I use

Yes I do. I keep it in notion or random .txt files.

todo.txt in Dropbox root folder. Windows notepad as an editor.