As part of the "Play at home program" some games have gone up free, limited time to collect, but forever to keep. You do not require PS+ for this. Anyone can download them, in their respective regions (I assume. I know NA/EU are covered.)
I would include links, but trying to download from a region not native to yours won't really work. Meaning you'd have the store page from my region and have to look them up individually anyway.
Horizon Zero Dawn Complete Edition IS HERE! (Until May 4th)
The following games are free from right now until I think april 22nd. (Some real gems here.)
Horizon Zero Dawn Complete Edition (PS4)
Abzu (PS4)
Enter the Gungeon (PS4)
Rez Infinite (PS4 & PSVR )
Subnautica (PS4)
The Witness (PS4)
Astro Bot Rescue Mission (PSVR)
Moss (PSVR)
Thumper (PS4 & PSVR)
Paper Beast (PSVR)