As you all know, SDK Tools, Revision 25.3.0 (March 2017) brought significant changes to the Android SDK commandline tools. Most notably, the android command is no more.
I used that command frequently in order to list my Android virtual devices: android list avd.
To do that now, just use emulator -list-avds
To launch the emulator with an avd, type emulator @avd_name, where avd_name is returned by the above command.