Hey there everyone! @nayelyz thank you for the tag!
It appears to me that the available options displayed are based on the OCF Type being used by the device as @milandjurovic71 mentioned. However, I want to get this information confirmed to be one-hundred percent sure so I have escalated this to hopefully provide additional insight to you all.
Changing icons is currently possible for contact,multi-sensors, lighting devices, and SmartTags.
Note: Some device types such as door locks and motion sensors, currently do not have the option to change icons.
I also wanted to provide the numerical count for the options available to be selected for Icon changes.
Switches/lights - Displays 8 options to select.
Outlets - Displays 16 options to select.
Contact Sensors - Displays 5 options to select.
Multi-sensors - Displays 9 options to select.
Smart Tags - Displays 29 Options.
I hope this message finds you all well!
^SamsungZell