Placed mini-fridge in world and now can't pick it back up

@rejohnson53  There's no way within the game to remove an object that's not on a lot, unfortunately, unless you can get a sim to use it, which it sounds like you can't.  If you're willing to use a mod, TwistedMexi's T.O.O.L. mod lets you delete objects not on lots.  You could remove the mod afterwards if you wanted.

Or you could revert to a previous save.  Here's how:

https://sims4.crinrict.com/eng/2014/09/save-games/#wiederherstellen