There’s no greater tool for a ‘Second Brain’, in my opinion. It’s fully customisable to suit your needs for all areas of interest. This is where I store my Kindle highlights, description thesaurus, dictionary of words I’ve looked up, project notes, daily tasks, personal journey, several versions of the Bible with verse-by-verse commentary, gardening tips and tricks and plans for the year, worldbuilding notes styled like wiki pages, character sheets, and beat-by-beat plans of my novels. It’s fully scalable with custom templates and plugins, and very well worth the investment of your time and energy.