On Collecting Quotes
More than a decade ago, a discovered a fun little app called Quotebook the app was deprecated within a couple of years of my discovery. By some miracle, it has continued to work. I have transferred from phone to phone and continued to use it for its intended purpose, collecting quotes from news stories, books and memes. As a backup, I also use individual text files named after the speaker/writer. Once that folder contained over 500 individuals. I created a GitHub repository to make it easy to share with others. Available as a ZIP archive or as single files you can find it here.
I prefer finding my quotes organically rather than harvesting tons of them at a time, but I will occasionally go looking for a quote on a specific topic. A good place to do that is here -
If you use IFTTT, you can get quotes emailed to you daily. I've been doing it for years. The day's choice goes out shortly after midnight, so it's always waiting for me when I wake up. You can get the same service with a free account.
Email me a famous quote every day - IFTTT
There are a few other quotes collecting apps available for iOS and Mac. I've tried them all.