Worthwhile to mention Sci-hub's telegram bot [1]. Forward any link as a message to the bot and it's instantly send you a paper.

Also worthwhile to mention Zotero's sci-hub integration. There's a guide on how to get it running here: https://medium.com/@gagarine/use-sci-hub-with-zotero-as-a-fa...

[1] https://twitter.com/sci_hub/status/731467465973174273

this userscript will automatically detect and link DOIs to scihub: https://greasyfork.org/en/scripts/36188-sci-hub-automatic-li...