Maxim Ananov reviewedDeskCoverFree alternative to HazeOver, UnDistracted and WindowFocus
 Not Recommended
Pros: 

Free

Cons: 

Copycat

Not shy about copying many elements of HazeOver app. I’m not talking about general idea: it’s down to menu structure, the same keyboard shortcut, some UI layout and even text along with app description phrases.

https://imgur.com/a/BkARx

Since the author explicitly promotes this app as a better alternative for HazeOver, do yourself a favor and try a free trial of the original app.

So frustrating and sad.

Maxim Ananov has used this product for one day.