As with all my add-ons, this was originally written for my own needs. My partner and friends have urged me to share.

Menagerie

• Allows you to select your favorite companions by check-marking them on the Companions Frame.
• Change to a different companion every ?? minutes (set by user).
• Automatically summons a companion if one is not already out.
• Smart summon, will not summon if in combat, death, stealth, mounted, vehicle or flying.
• Select ground and flight mounts by check-marking them on the Mounts Frame.
• Key Bindings for Smart-Mount to automatically pick a ground or flight mount.
• Very light weight, with no predefined data it is ready to go when new mounts and companions are released.