Here are some useful links for further reading (we have discussed most of these systems in Grokking the Advanced System Design Interview':

1. Dynamo - Highly Available Key-value Store

2. Kafka - A Distributed Messaging System for Log Processing

3. Consistent Hashing - Data distribution with minimal disruption during scaling.

4. Paxos - Protocol for distributed consensus

5. Bigtable - A Distributed Storage System for Structured Data

6. Gossip protocol - For failure detection and more.

7. Chubby - Lock service for loosely-coupled distributed systems

8. ZooKeeper - Wait-free coordination for Internet-scale systems

9. MapReduce - Simplified Data Processing on Large Clusters

10. HDFS - A Distributed File System

11. Cassandra - A distributed, decentralized, scalable, and highly available NoSQL database.