Here's a rough technical walkthrough:
Upon sync we'd use Patreon's oAuth API to see what developers the user is an active patron of. This would be stored in a table in the database. The user would then select which developers to show on their profile, the others would remain hidden from everyone.
Every x days we'd request the list again from Patreon's API, updating the database, and if the user is supporting a new developer who has opted in, we'll send a notification telling the user there is another creator they can show on their profile, if they so wish.
Users would also be able to 'unsyc' at any time, by clicking a button within Patreon's settings page.
This would have no noticeable impact on our infrastructure, the only information we'd store is the developers the user is a patron of, and the user specific API key needed to fetch that list from Patreon, which would be AES encrypted in the database.
I think Graphtreon does a better job of this than we ever could, and is far more encompassing.