@Torq offered a helpful comparison of Closed back here Closed back headphones - #7 by Torq
At that time, he found the Aeon Flow closed to be the most isolating.
MrSpeakers AEON Flow Closed
The exception that makes the rule … this is a better sounding, more neutral, and more open sounding headphone than its open-back cousin … for the same price. Likes power - otherwise they’ll sound congested and lifeless/dull (not something to use straight out of a phone). Tonality can be tweaked with included filters. Not a detail-monster (though better with the black filter), but otherwise a very engaging and convincing listen. Looks fantastic, excellent comfort, supplied cables are a sane length, non-microphonic and extremely flexible. Offers the best isolation I’ve so far found in a passive headphone.