How many games are there?
PS4 wasn't mentioned at all outside of GTA but I imagine a good number of these titles will also hit the platform. I find its quite easy to guess from the visuals.
Spiderman; With only 2 years in development, built for the same engine and a launch title, I really expect this to land on the PS4.
Grand Turismo 7; Game obviously looked good but it looked very current gen. You can see the low poly count on the drivers hands and on elements of the car interior, as well as the low res shadows.
SackBoy Adventure; Doesn't really need explaination. The textures certainly look build for current gen, infact I'm sure we've seen better fur and embroidery.
---------------------------------------------------
So my assumption is that the actual PS5 exclusives from Sony are
Returnal
Demon Souls Remake
AstroPlayground (because of the controller)
RatchetandClank
Horizon 2
Destruction All Stars (Maybe)
Hopefully we see a few of these next gen exclusives at launch outside of Astro Playground which is confirmed as preloaded.