Is Craigslist the Last Real Place on the Internet? Millennials are still using Craigslist to find jobs, find love, and even to cast creative projects--eschewing other AIand algorithm-dominated online spaces. The writer and comedian Megan Koester got her first writing job, reviewing internet pornography, from a Craigslist ad she responded to more than 15 years ago. Several years after that, she used the listings website to find the rent-controlled apartment where she still lives today. When she wanted to buy property, she scrolled through Craigslist and found a parcel of land in the Mojave Desert.

White dwarfs (WDs) polluted by exoplanetary material provide the unprecedented opportunity to directly observe the interiors of exoplanets. However, spectroscopic surveys are often limited by brightness constraints, and WDs tend to be very faint, making detections of large populations of polluted WDs difficult. In this paper, we aim to increase considerably the number of WDs with multiple metals in their atmospheres. Using 96,134 WDs with Gaia DR3 BP/RP (XP) spectra, we constructed a 2D map using an unsupervised machine learning technique called Uniform Manifold Approximation and Projection (UMAP) to organize the WDs into identifiable spectral regions. The polluted WDs are among the distinct spectral groups identified in our map. We have shown that this selection method could potentially increase the number of known WDs with 5 or more metal species in their atmospheres by an order of magnitude. Such systems are essential for characterizing exoplanet diversity and geology.