I'm the DM of a 5th-level party whose PCs have a handful of illusion spells in their repertoire. The players have on at least one occasion mentioned the idea of using one of these spells to hide some important object -- not by covering it with the image of another solid object, but with an illusion of open air. The question "Can you create an illusion of empty space?" already covers that scenario, where the accepted answer strongly implies it shouldn't work. But what about spells that are expressly designed to make objects invisible?
Invisibility (and Greater Invisibility) works on creatures and their equipment, but the types of objects the players want to hide are things that can't exactly be carried on someone's person (e.g. a cart, a statue, a mound of dirt from digging a deep hole). The only spell in the Player's Handbook I found that describes making an object invisible is Sequester, but it's overkill for this situation (7th-level spell, 5k gp in material components, also blocks divination, lasts until dispelled).
Are there any other effects (spells, items, or otherwise) that can make an object or volume invisible? I'll accept any official or playtest publication as a valid resource. I don't necessarily need it to be available/affordable to 5th-level PCs, but I'd prefer something near the level/value of Invisibility, since I'm looking for similar utility.