Ways to get free and legal access to research papers as a researcher I’ve discovered that website like ResearchGate offer the possibility to ask the paper editor to provide his paper for free. Many are collaborating.

Are there any other ways for researchers to obtain free access to papers?
I always use the following methods to get many inaccessible papers. 


Open Google Scholar.
Search the title of the paper.
Click see all versions (you can see many places where the same paper is available)
Check one by one whether they are downloadable 


Another method, I always use when I really need an inaccessible paper, is just to write an e-mail to the corresponding author to send that paper. My experience is that I have always received the paper in a return email.