Probably “labubu”. The -(e)ne suffix is mostly used with animated nouns, and since they’re toys I’m guessing people would use the inanimate with them instead.

…unless it’s part of some odd construction like “kings of labubu” (lugal labubu-k-ene) or “shepherds of labubus” (sipad labubu-k-ene) . Then you get the plural mark, but that’s because of “kings” (lugal-ene) and “shepherds” (sipad-ene); those Sumerian case/number marks behave more like clitics than suffixes.

You can also stack them, and it gets messy (like, “labubu-k-ak-a-ne” tier).