NoSQL Databases

Document-oriented:

• MongoDB: Flexible document store for semi-structured data
• Couchbase: Distributed NoSQL document database with SQL-like query language
• Amazon DocumentDB: MongoDB-compatible document database service
• Azure Cosmos DB: Globally distributed multi-model database

Key-Value Stores:

• Redis: In-memory data structure store used as database, cache, and message broker
• Amazon DynamoDB: Fully managed NoSQL database with key-value and document support
• Riak: Distributed NoSQL key-value data store
• Memcached: In-memory key-value store for caching

Wide-Column Stores:

• Apache Cassandra: Highly scalable, distributed NoSQL database
• HBase: Hadoop database for random, real-time read/write access
• Google Bigtable: Scalable NoSQL database service
• ScyllaDB: High-performance Cassandra-compatible NoSQL database

Graph Databases:

• Neo4j: Native graph database for relationship-based data
• Amazon Neptune: Fully managed graph database service
• JanusGraph: Distributed graph database
• TigerGraph: Scalable graph database for real-time analytics

Time Series Databases:

• InfluxDB: Purpose-built time series database
• TimescaleDB: PostgreSQL extension for time series data
• Prometheus: Monitoring system and time series database
• QuestDB: High-performance time series database