We do not permit any mention of Patreon accounts, or allow authors to solicit Patreon contributions on AFF. Fan fiction exists in a grey area of the Fair Use provisions of copyright law, and one of the requirements is that the author makes no money from material copyrighted by someone else. Should the owner of the copyright choose to do so, the author could be sued for monetary damages, and the site would be required to at the very least remove the author and all works, or could be served with a cease and desist order preventing ANY fan fiction involving that copyrighted material entirely, or could be sued along with the author for copyright violation.
You can read the relevant discussion of fair use here: http://fairuse.stanford.edu/Copyright_and_Fair_Use_Overview/chapter9/9-a.html
So, while we all want to support authors, we cannot allow any Patreon or other funding sites to be mentioned here, or for authors to offer to write fan fiction for commissions.