I'm pretty sure you all will soon see OP7 leaks flooding on your timelines since I can confirm that the launch is in May. It seems like the the name of the more expensive smartphone is indeed gonna be OnePlus 7 Pro and tagline will be "Go Beyond Speed". Although, it may change. pic.twitter.com/a42yjY0RY0

— Ishan Agarwal (@ishanagarwal24) April 10, 2019

BTW, I have just got the model numbers of the OnePlus 7 Variants confirmed so here they are:
GM1901,03,05 -> OnePlus 7
GM1911,13,15,17 -> OnePlus 7 Pro
GM1920 -> OnePlus 7 Pro 5G
PS: Still not 100% Sure, maybe for development only.https://t.co/UnInwWs7FI#OnePlus7 #OnePlus7Pro pic.twitter.com/kYvjLyBkLC

— Ishan Agarwal (@ishanagarwal24) April 9, 2019