What are /r/GreatFilter's favorite Products & Services?

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Unpaywall

An open database of 23,154,885 free scholarly articles.

We harvest Open Access content from over 50,000 publishers and repositories, and make it easy to find, track, and use.

Get the extension

https://unpaywall.org/

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The link to the Unpaywall extension would be helpful in the sidebar. Suggested it on many subs, yet no mods have included it. If I don't include it with a paywalled link, half the time someone says "it's paywalled!", but I don't always remember or want to. It's tedious when one shares paywalled links daily.