To create these games we use a software app called Desmos Activity Builder. This app was developed as a companion to Desmos' free graphing calculator and was used primarily to create activities related to math. In this case, the Desmos version of "Guess Who?" is called Polygraph. And even though this app was developed for mathematics, this Polygraph activity creator can easily be used to create these "Guess Who" type games for any subject area. The hard part, really, is just coming up with 16 related images for your students to look at and describe. Watch the video below to see how to create your own.
To help out, I have created some for a few subject areas
Canadian Landscapes: Desmos Polygraph
Identifying Art: Desmos Polygraph
The Periodic Table: Desmos Polygraph
Canadian Iconic Symbols (for French): Desmos Polygraph
And, of course, There are a pile of them created for math: Desmos Polygraph