Being able to see in tooltips if a Vendor or Mob had something you needed was really nice.

This a nice feature of https://www.curseforge.com/wow/addons/recipe-radar-classic -- but that's no longer being developed.

ATT has the same feature for Vendors, but not for Mobs -- at least not that I've seen.

Oh, and it'd be great to see a tooltip on dungeons and raid entrances, showing what all drops inside! (=