Here's an article from last summer: http://www.extremetech.com/electronics/188756-verizons-volte-rollout-will-kill-off-cdma-and-allow-unlocked-lte-phones-too

It looks like as long as the phone operates on the 700 MHz LTE band (band 13), the phone will work with Verizon. You have to check the specs on the specific phone you're looking at to see what bands it operates on. If it uses 700 MHz, I'd then do a google search for the specific phone and Verizon to see if you can find out if others have been able to use it.