One movement I like a lot is the Iso-hold band row. It's basically a band row with a hold at the maximum contraction point to bring up your ability to hold at the top.
How do I do these?
Simply do a seated or standing band row - there are dozens of videos of this movement out there. Instead of just pulling back and then just letting the band pull back into the next rep, hold for a 2-second count at the top at maximum contraction.
You can also do these with a cable row, just adding a band for resistance. You'll need a sturdy setup so you can link the band around the handle and around the unit.
You can increase the difficulty of these by doing longer contractions at the top and/or using a stronger band. You can also add an extended eccentric element by resisting the band's pull back - a 2-second hold with a 2-second eccentric is going to be a whole different and harder exercise than just letting up the tension on the band.
Why am I doing these?
It does a few things. If your weak point in rows is that final contraction at the top - you've got problems keeping the weight locked in to your side at the very top - this will work that directly. Second, it changes up the resistance a little. You have to start the movement quickly or you won't be able to extend the band fully. With just the band, it can be a good movement for shoulder and upper back stability - think of the top of a band face pull, with your shoulder blades retracted together. That's where the band pulls the hardest.
I specially do these, and have clients do them, to improve the ability to hold on to a heavy contraction at the top. This is useful for folks hanging from bars, hanging from ropes, or hanging from opponents. But it's not purely isometric strength, because you need to be able to get the band back each rep. It's a good combination. Just don't let your ego get ahead of you - if you go too heavy on the band and can't get the upper back fully contracted and the band pulled to the ribcage (think wrist-to-ribs, or touching the band to your body) you're missing the critical element of the movement.