Our DS uses LAMP.
https://lampwflapp.com/
One thing that surprised me about LAMP was that the icons are less about being able to read the word, and more about memorizing where it is in the system, similar to how adults rarely look at the keyboard while typing. DS is much more fluent in LAMP than I am. His SLP added icons to his device as he learned them.
But there are other system options that are more image based or organized differently.