You can plug several types of external storage devices into an eSATA port, including:

1. External Hard Drives: Many external hard drives are designed with eSATA ports for high-speed data transfer. These drives often offer better performance compared to those using USB 2.0 or FireWire.

2. External SSDs: Solid State Drives (SSDs) with eSATA connections benefit from high-speed data transfer, making them ideal for applications requiring quick access to data.

3. eSATA Docking Stations: These are devices that allow you to connect internal SATA hard drives or SSDs externally via eSATA. You can insert a bare drive into the docking station and then connect it to your computer using an eSATA cable.

4. eSATA Enclosures: These are cases that house a SATA drive and provide an external eSATA interface. They allow you to convert an internal SATA drive into an external drive with high-speed connectivity.

These devices leverage the high-speed data transfer capabilities of eSATA, providing a robust solution for connecting and accessing external storage with minimal latency and high performance.