I was lucky enough to attend the Searchmetrics Summit 2017 in Berlin in November. I thoroughly enjoyed some of the presentations. You can view them all here: http://pages.searchmetrics.com/201711-Summit-Berlin-keynotes.html
Probably my favorite presentation was the keynote by Marcus Tober, Founder and CTO of Searchmetrics. He spoke about the importance of transitioning from general Ranking Factor studies to Industry specific. I found this quite interesting. Here are his slides and also a link to the recording of the presentation: How Search Data Helps Improve Your Content Strategy
As Marcus references in his presentation, Searchmetrics has conducted 5 Ranking Factor studies for unique industries:
eCommerce
Finance
Travel
Media
Health
At my current job at Betsson, we’ve conducted our own Ranking Factor study, manually, of the iGaming industry and used our findings to educate our internal stakeholders, prioritize our SEO efforts and guide our product roadmap.
I also pay close attention to Local SEO Ranking Factors for optimizing my dad’s blog.
I just found this lesser known ranking factor study from Branded3 and plan to review it in more detail soon.