RenPy being based firmly upon python will do anything python can do.
Patreon
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that allows for
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to be extracted... So your RenPy game should be able to use it. (At least, in theory).
However. I strongly suspect that Patreon only show a full list of Patreons to the actual creator. So although such an API does exist, you'd probably need to code your security credentials into your game so that the code could access the list. That's a massive security no-no.
You could use a bit of web-scrapping code, but only if a non-patreon user can see the list of subscribers (I'm thinking probably not).
You could copy/paste the list into something like an excel spreadsheet and then use that to format things in a way that can be copy/pasted into your RenPy code... but that would be overlooking some other points...
Are you sure all your Patreon's would consent to their names being included in a AVN game? You'd effectively taking a piece of largely private information and making it public. Not everyone is going to appreciate that.
Finally, there are going to be a bunch of people who are going to immediately ditch your game just because it tried to make an internet connection. Now the majority of those won't be paying customers - so perhaps the answer is "so what?". But RenPy games are "usually" offline games.
Is it possible?... In theory, yes.
Should you be trying?... Probably not without some form of prior consent.