Let us filter search by project type, so we don't have to sift through dozens of modpacks to find the mod we're looking for, for example.
And persist our choice for version and sorting. A proper advanced search should:
Be able to select what's being sought (Modpack, mod, world, resourcepack ), category (cosmetic, magic), exclude mcreator mods (many crashes stand-alone servers), sorting, version
Results should show name, author, activity (comments, issues, modpack inclusions), creation and update date.
The mod pages should show, in addition to existing info, clientside (but won't hurt the server), both, only local (I.e. will crash the server due to using clientside API regardless of environment, e.g. mcreator mods), only serverside (i.e. doesn't require the client to have it installed for connecting to the server)