Various types of electronic devices may be mounted in a chassis in order to facilitate interfacing with the devices, containing the devices, provide cooling systems which may remove heat from the electronic devices, etc. Delivering adequate cooling air flow to each electronic device in a chassis may be an important issue for the proper functioning, lifetime, or other characteristics of electronic devices contained in a chassis. Some electronic devices may be particularly challenging to cool due to various design characteristics. Other electronic devices may have other requirements that are not well served by existing chassis designs. For example, some electronic devices may benefit from additional electrical and/or thermal connections. Embodiments presented herein describe a novel design for a modular card cage accessory that may be configured to modify air flow and/or to meet particular requirements of an electronic device in a chassis, among various possibilities.