Micah Sweet
Level Up & OSR Enthusiast
I think the clockwork horror appeared in a 5e supplement somewhere, although it might have been 3rd party.My favorite Spelljammer creature was the clockwork horror, which is one I could see making a comeback (they're basically the Replicators from the Stargate franchise, except they appeared first). Others I was fond of (but are less likely to return) are the plasman, spiritjam, and survivor.
It's just not space without the Borg!