The article directly mentions several.

> Teams across AWS that build some of its flagship products—from storage (e.g., Amazon S3, EBS), to databases (e.g., Amazon DynamoDB, MemoryDB, Aurora), to compute (e.g., EC2, IoT)—have been using P to reason about the correctness of their system designs.

Later it more specifically mentions these (I probably missed a few):

S3 index, S3 ShardStore, Firecracker VMM, Aurora DB engine commit protocol, The RSA implementation on Graviton2

(EDIT: formatting)