I've been using the 3M Gold privacy filter for about a month and it works great on my MacBook Air. I chose gold because it's a less common color and also because my MacBook Air is also gold, although it will obviously work on any 13-inch MacBook. The MacBook is just as easy to close as it is without, and offers decent privacy from side viewers (of course, anyone directly behind you can see what you can see). I recommend it.
Enhanced Privacy with 3M Privacy Filter for 14 Inch Widescreen Laptop - Flip-Share COMPLY Attachment, Gloss/Matte Reversible, Blue Light Reduction, Screen Protection, 16:9 Aspect Ratio (PF140W9B)
10 Review
ποΈ Enhanced Eye Protection: 2 Pack 13.3" Laptop Screen Protector - Blue Light Filter, Anti Glare & Blue Light Blocking Screen Protector for All 13.3" 16:9 Laptops (Diagonal Length 13.3", Bezel Not Included)
10 Review
π PYS MacBook Pro 15 Privacy Screen Filter with Webcam Cover - Protection Shield for MacBook pro 15.4 inch (Late 2016-2019 Including Touch Bar), Anti-Spy Privacy Screen Protector, Perfect Fit
10 Review
Solitude Screens - Slimmest Magnetic Privacy Screen for MacBook Pro 16 inch - Dual-Sided Anti-Glare MacBook Pro 16 inch Screen Protector - Privacy Screen for MacBook Pro 16 inch Laptop Screen (2019+)
10 Review