This product worked great on my PS4 but only after I reformatted it to Fat32. If you don't reformat it won't work (at least it doesn't work for me). This is more Sony's fault than the flash drive manufacturer's. Sony had to develop software to work with regular flash drives, not ones that need to be specially formatted with small partitions.
Kingston DataTraveler SE9 32GB USB 2.0 Flash Drive for Reliable Data Storage (DTSE9H/32GBZ)
69 Review
Samsung BAR Plus 128GB USB 3.1 Flash Drive - 400MB/s - Champagne Silver (MUF-128BE3/AM)
65 Review
Sandisk Ultra Flair 128 GB Silver USB Flash Drive: Reliable and High-Speed Storage
65 Review
Samsung BAR Plus 128GB - High-Speed USB 3.1 Flash Drive Titan Gray (MUF-128BE4/AM)
67 Review
Shock-Resistant Transcend StoreJet 25M3 USB 3.1 Slim Portable Hard Drive with 500GB Capacity
99 Review
2 TB External HDD ADATA DashDrive Durable HD650, USB 3.2 Gen 1, Blue
55 Review
18 TB External HDD Western Digital WD Elements Desktop, USB 3.0, black
95 Review
π Seagate Expansion 3TB Portable USB 3.0 External Hard Drive (STEA3000400) in Black
60 Review