Shuei Yoshida said in an interview to Dengeki Playstation that Sony is working on many new unannounced titles.
Things I'm looking forward are:
1)New partnership with From Software after Bloodborne
2)Sucker Punch new IP
3)New Guerrilla Cambridge game after Killzone Mercenary in 2013 (still one of the best VIta games).
About E3 they seem to have their hands already full even with zero surprises.
For them it would be enough to showcase RDR2, TLOU2, GOW, Spiderman, FFVIIR,Shenmue 3, Crash Remastered,Detroit, GT Sport, Death Stranding, Destiny 2 and Star Wars Battlefront 2 and their E3 would be already done as one of their best ever.
So it's kinda incredible to think they might have further surprises to announce.