So in the process of reading Homestuck, I found out that Dave's iconic sunglasses are, in-universe, a pair worn by Ben Stiller in a film that has not been named but is almost certainly Starsky and Hutch since they appeared a lot in Problem Sleuth, with the bust they appear on in that comic almost identical to the photo of them hanging in Dave's room. It seems likely that their appearance in Homestuck is just a reference to Problem Sleuth.
Despite the fact that the most iconic piece of one of the main characters of a once massive comic franchise exists irl, I've been unable to track down the whereabouts of these sunglasses. I found one Reddit thread from eight years ago asking about them, with only one reply pointing to a website which sells props from movies saying that they may have at once point had them because they have props hailing from the same film, but the site doesn't seem to archive sold listings, so if they did it's a dead end unless a third party site archived the listing.
I'm kind of shocked people aren't looking for them. The Dave Strider sunglasses exist in real life, and people obsess over that little irony-poisoned asshole. He's probably the single most popular transmasc namesake on the planet. You'd think his iconic sunglasses would be culturally valuable and worth preserving, maybe even worth putting in a queer museum somewhere if such a thing exists, but I've only been able to find one instance of somebody caring, and it's from an obscure Reddit post from almost a decade ago. What gives?