I couldn’t verify a live count of “Oompa Loompa” costumes left in Roblox from the information available here. The search results only show Roblox-related outfit videos and general costume references, not an official Roblox inventory count or remaining stock number.

If you mean a specific Roblox item, the only reliable way to know how many are left is to check that item’s page inside Roblox, where limited-availability items usually show their current remaining quantity. If you mean user-made “Oompa Loompa” outfits rather than an official item, there isn’t a single global count because players can create countless versions.