Where can I find missing iMovie project from 2016?

I assume that you are talking about a video that has been exported from an iMovie project and not talking about the project itself. The project itself would be located in the iMovie library in which it was created, and would be accessed through the iMovie app. So you would need to locate the app and its iMovie library. Check your Movies folder and your Applications folder, plus any external drives to which you might have saved them.

Regarding exported movies, as mentioned by MrHoffman in a previous post, a Spotlight search would be a good place to start. Video files can be stored almost anywhere that you want. Likely places are the Movies folder or documents folder. They can be stored in the Photos app as well. If they cannot be found on your computer perhaps they were stored on an external drive or maybe on your previous computer. You might also go to iCloud.com and see if your videos are stored there.

-- Rich

Enter some text from the movie title cards or interstitials into Spotlight, if you remember any of those.

See if that finds it.

Or select a kind of file being a movie, using a Finder file search.

But otherwise, yes, you’re going to have to search.

Only you would know where you might have saved it. You can search your computer for any movie file and see what appears.