For those on iOS with a device that supports 3DTouch, there’s an option to add a new card in the menu that pops up from the Trello app icon on the home screen. Granted that 3DTouch features are not easy to discover though.

I use Google Keep, Google Docs and Trello.

- Google Keep for quickly jotting down new ideas on the go (usually just a line or two so I can remember). This is my temporary record.

- Then, when I have time at the end of day, I add to to my document in Google Drive with more details, description, etc. This is my permanent record.

- When I'm ready to work on something, I add it to Trello with specific tasks, deadlines and reminders. This is my task manager.

One thing I'm failing to consistently do is to revisit old ideas periodically and remove the old ones I no longer deem worthy exploring.

+1 to this. I have a board with different lists regarding the overall category of the idea. (App, website, thing, etc.) Along with that I use labels to further categorize within the lists.