Here's a scenario that identifies the issue I'm having creating some frustration: I find myself having to sort through megastores of ~40 lines of items across many pages when 1 line is all I'm concerned with. I'll run into a ton of plain white armors for example when I search "eth lacquered plate."
I've also had difficulty search for amulets, rings, boots, and gloves with specific mods I want all on the same piece. It got me to the point where I was searching "boot" every day or so and manually reading instance I found in search with control + f to help sift. I don't have the patience to do that anymore, at least not so frequently.
A simple multi-tag search feature might be an easy solution: i.e. if I put in for tag 1 "eth" or "ethereal", tag 2 "sup" or "superior", tag 3 "lacquered plate" or "lacquered armor", I shouldn't get any result that doesn't have these 3 tags in the same line. This could exist already for all I know?
Having sellers choose certain dropdowns to help sort gear under subcategories might also be helpful and used in conjunction, i.e. a main category might be amulets which falls into two subcategories of crafted and non, then class type, then skill tree type.
Having them set mods, like 15% fire resist, 5 to battle orders, which are searchable based on > < = certain numbers could also be helpful.
https://d2.maxroll.gg/d2planner/ gives what mod ranges can be for certain items though doesn't seem to include crafted ranges, maybe there's a better for resource for that information.