GDSE has a bunch of issues with its links having major perception issues across the board. Could link colors on this site's main, meta, and chat please be revisited? My request would be that our links should be clearly distinguishable from regular text in all three site areas, and preferably visited and unvisited links would be distinguishable from each other.
Some of these issues have sat reported for several years unactioned. On meta and chat they incur severe legibility issues, and that's for people with good eyesight and well-adjusted monitors.
Chat: We can hardly see links at all. Reported in 2014: Can we get a hyperlink style for chat that is less subtle?, Link color in chat is too similar to normal text color. This is impactful enough that when I'm linking people to stuff in chat, I have now been making a habit of pointing out there is actually a link there or using link emoji, so that they don't miss it.
Meta: Visited and unvisited links have significant visibility issues. Visited links are a dark grey, which is hard to tell apart from the off-black regular text (these have a 2.6:1 color contrast ratio, which is poor at this font scale). Visited links aren't great either: that dark red only has a 1.2:1 color contrast ratio versus regular text, which makes it an extremely difficult-to-detect colour difference.
Main: Visited and unvisited links look practically the same. Reported in 2012: Link Colors for Visited and Non-Visited Links too Similar. This is the only place we can at least actually clearly tell links apart from regular text.