Maintaining stability in an islanded microgrid is an essential task, especially with the increasing penetration of inverter-based resources (IBRs) due to the advancement in power electronics. Unlike conventional synchronous generators (SGs), IBRs have low inertia, posing significant stability challenges. To address the stability issues, grid-forming inverters (GFMs) and virtual synchronous generators (VSGs) are proposed to enhance damping and emulate the dynamics of synchronous machines. However, the distinct behaviors of IBRs and SGs can lead to instability in hybrid-DER microgrids without proper coordination between IBRs and SGs. A feedback control system for both IBRs and SGs can be deployed to stabilize the hybrid-DER microgrids. For effective operation, several technical issues can be considered in the feedback control loop. Partial state feedback control, relying only on measurable states without the need for an observer, is used instead of full state feedback. Decentralized state feedback uses local states as inputs without the requirement of a communication system.