We make a list and we check it twice? There are 150 icons in the set as of the latest release. We’ve chosen them over the years based on feedback from customers, our own needs, what you might expect I think. We hadn’t thought of Yahoo or Amazon, I’m not sure anyone has requested those before, I’ll add them to our list of ideas for a future update. As far as Discover it’s no intentional slight, we weren’t setting out to cover every major type of credit card, we figured simply having numerous differing card options was enough, but we’ll add that to the list, too.
There’s no way to add new icons right now, but once we tackle image storage (and sync) we can take a look at that (we’d want to store your images in the encrypted database and have them transfer with your records when you sync.)