Here's a link to all the free themes and avatars. They will be leaving the store on mobile and the web so this is probably the easiest way to get it before
Red Dead Redemption 2 Sells 24 Million Units, Celebrate with Free PSN Avatars
New Free Avatars Available On PSN Include Bloodborne, The Last Of Us Part 2 and God Of War - PlayStation Universe
Wario64 on Twitter: "Free Final Fantasy XIV avatars on PSN https://t.co/uuqrdn9mp0 https://t.co/Mvvw31Ad7N" / Twitter
FINAL FANTASY XIV ar Twitter: "(EU) #FFXIV themed avatars are available for free download on the PlayStation® Store! https://t.co/4g4IEpMRV1 https://t.co/HZrGCs1VNy" / Twitter
PlayStation Store PS3 Avatars Rant – koukoupuffs
Screenshot] FREE Shadow of the Colossus avatar pack for people who have played SotC on PS3. Contains avatars for each colossus. : r/PS4