Minecraft wiki entry for Obsidian_farming, associated text: Linking a zombified piglin gold farm to a piglin bartering farm gives you lots of loot from bartering, such as nether quartz, gravel, Soul Speed enchanted books and iron boots, iron nuggets, and obsidian, along with many others. You can get a full double chest of obsidian after an overnight AFK session. If one's gold farm is in the nether, it can be linked with a piglin bartering farm fairly easily. If instead, you want to build your gold farm in the Overworld powered by nether portals, you might want to consider getting obsidian in another way first, such as other methods shown on this page, then you can switch to piglin bartering.