Simple database model that stores data as key-value pairs. Like having a giant dictionary where you can look up any value using its unique key.
Session storage systems use key-value stores to quickly retrieve user session data using session IDs.
All provide managed, highly scalable NoSQL storage. DynamoDB and OCI NoSQL are key-value/document databases; Cosmos DB Table API offers a key-value style table model; Bigtable is a wide-column store often used like a key-value store for large-scale, low-latency lookups by row key.