UPDATE 17/08/2016 5.39pm: Sony issued an update explaining that Retro/Grade was never supposed to be part of the promotion this month. Its inclusion was an error, so Sony has removed it and in its place offered Tom Clancy's EndWar for PS3.
As it turns out, Retro/Grade was a repeat offering in Europe, which has never happened before in the PS Plus Instant Game Collection. However, it is a new offering in North America, where it remains part of the August promo.
ORIGINAL STORY 27/07/2016 5.43pm: PlayStation Plus' Instant Game Collection - i.e. free games for subscribers - has been revealed for the month of August.
PS4 titles include Tricky Towers and Rebel Galaxy. The former is debuting next month and offers a physics-based competitive spin on Tetris. Players build towers based on Tetris blocks, but they're subject to physics and players can cast spells to stabilise their rickety constructions or sabotage their opponents'.
Rebel Galaxy is a space combat game where you control massive ships in a procedurally-generated universe. It launched late last year on PC before coming to consoles in early 2016.
PS3 titles included in the promo include gangster epic Yakuza 5 and guitar-controlled arcade adventure Retro/Grade. The timing is pretty good for Yakuza 5, since its prequel Yakuza 0 just received a western release date.
Vita freebies for August include rhythm game Patapon 3 and retro arcade game Ultratron, which is also available on PS4 and PS3.
July's Instant Game Collection expires soon, so if you haven't already now would be the time to snag Furi, Saints Row: Gat Out of Hell, Paragon early access, Fat Princess, Call of Juarez: Bound in Blood, Prince of Persia: Revelations and Oreshika: Tainted Bloodlines.