headphones to use with a Chord Mojo

I'm open for ideas on headphones to use with a Chord Mojo headphone amp.

Any folks have used with a Mojo that turned out special?

Currently using original Sennheiser Momentum mostly with it. They need to be sealed and no sound leakage...no open back phones. Also comfortable when laying down since I mostly use this setup at night in bed before going to sleep.

I also have Grado sr80 phones that I like a lot with the Mojo but those are open back.

The Sennheisers sound good but looking for an alternative to their more laid back somewhat bass heavy sound.  

I would lean towards Audio Technica at present.   Any insights on specific models appreciated.
I haven't tried them with Mojo specifically, but really liked the Focal Elegia when I had them for 15 days or so. There was nothing wrong with them per se, but my preference leans towards open back so decided to replace them with Focal Clear. Given that Mojo has a slightly warmer sound, Elegia which is slightly on the brighter side, might complement them well.
Not sure what your budget is, but take a look at Sony MDR-Z1R.  I wear them to bed sometimes.  They're kind of big, but are pretty light and very comfortable.  Lots of detail, fairly neutral, maybe a little bass heavy. 

My favorite bedtime headphones are Sennheiser HD 6XX, super comfortable, but you already have Senns and these are also open back and probably sound similar to your Momentum. 

I don't have any experience with the Chord.  I'm using Sony's TA-ZH1ES headphone amp.
I can’t speak directly to the  Chord Mojo because I haven’t owned one but i’ll add something about headphones. I have always been a Stax guy, Lambdas first then the 009s. Recently, I wanted to try a closed back phone so I bought a pair of Audeze LCD-XC here on Audiogon. I really like them and friends have said they prefer them to the Stax. I believe it is the comfort of the ear pads, who knows. I would take a look at the extensive line of phones from Audeze before you make the final decision.
I have the Audeze LCD-XC. They sound great and are very comfortable, but they're on the heavy side. I've always been afraid to wear them while listening in bed. I worry that I'll fall asleep with them on (which I do often) and drop them off the side of the bed at some point during the night (which I always do) and scratch up their beautiful finish. 
Maybe have a look at the 1More Triple Driver Over Ear ‘phones.  Not sure how they’d pair with your Mojo, but sounds like they may offer more detail than your Senns from the mids on up.  Best of luck.