Nothing automated. You could add IF to the Extra field and sort on that. It might be possible to write a plugin to automatically retrieve IF based on journal title/ISSN.
That said, a journal’s impact factor is unrelated to study quality, so if your aim to sort papers by quality/relevance/rigor, etc., I would suggest an alternative approach.
Honestly, there isn't really a way to evaluate the quality of a paper other than by reading it. You could use tags, notes, or ratings of your evaluations in the Extra field.
You could pull in the citation count for the paper from Google Scholar using the Google Scholar Citations plugin and sort on those. Note though, that citations are also not a great indicator of study quality—lots of citation happens without people actually reading the papers, and papers are also cited for many reasons (perhaps the study is good, perhaps it is being cited as an example of poor research, etc.).
There's also a problematic feedback loop in scholarship, where often-cited papers are cited more and more. (This is especially the case for overview/background papers used to introduce a concept or method, where one just seems to become the go-to paper for everyone to cite about that topic, without really exploring the other options out there. It's usually a reasonably good paper, but not necessarily representative of all of the other papers out there you might not find as easily.)
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That said, a journal’s impact factor is unrelated to study quality, so if your aim to sort papers by quality/relevance/rigor, etc., I would suggest an alternative approach.
You could pull in the citation count for the paper from Google Scholar using the Google Scholar Citations plugin and sort on those. Note though, that citations are also not a great indicator of study quality—lots of citation happens without people actually reading the papers, and papers are also cited for many reasons (perhaps the study is good, perhaps it is being cited as an example of poor research, etc.).