When using MySQL Enterprise Monitor’s agentless installation, some key features that are available include MySQL Replication monitoring, MySQL Query Analysis data, and security-related advisor warnings. MySQL Replication monitoring is crucial for keeping track of replication topologies and statuses. MySQL Query Analysis helps in identifying and optimizing problematic queries. Security-related advisor warnings are essential for maintaining the security posture of the MySQL server. Other system metrics such as CPU utilization, operating system memory utilization, and network-related information typically require agent-based installation.