PLOS uses this logo for open access: <a href="https:&#x2F;&#x2F;commons.wikimedia.org&#x2F;wiki&#x2F;File:Open_Access_logo_PLoS_white.svg" rel="nofollow">https:&#x2F;&#x2F;commons.wikimedia.org&#x2F;wiki&#x2F;File:Open_Access_logo_PLo...</a>. (an open lock) Based on that Wikipedia uses a closed lock to indicate paywalled sources: <a href="https:&#x2F;&#x2F;commons.wikimedia.org&#x2F;wiki&#x2F;File:Closed_Access_logo_alternative.svg" rel="nofollow">https:&#x2F;&#x2F;commons.wikimedia.org&#x2F;wiki&#x2F;File:Closed_Access_logo_a...</a>. So how about these: [Closed lock] [Open lock]? (TIL HN doesn&#x27;t support emoji) I think reddit also allows image use via CSS.