Contrary to popular belief (Considering Disney's own convention, D23, is in Anaheim in August), The Big M will be returning to Hall H after a year's absence.
Seeing as how WB/DC will not make an appearance, the floor is essentially theirs, unless you are like the OP and really hope that Sony "Figure It Out" Pictures will give us a Bloodshot trailer.
With "Endgame" Out of the way and "Far From Home" released a few weeks prior, the question remains; What will Marvel show? Possible Black Widow footage, as well as the official announcement of Doctor Strange 2, a logo for Guardians 3, and a possible casting choice for Shang-Chi.
SDCC takes place from July 18th through the 21st.