I am working with AEM ARCH 13 project and wasn't able to see templates from my templates folder in ui.apps. After some research, this is what worked for me:
STEP 1: Select the website and click on the Properties menu:

STEP 2: On the next page, click on the Advance menu:

STEP 3: Scroll down to Template Settings and click on Add. Update the new text field with the path to your templates folder (or to the templates you would like to see on the Create Page)

Good Luck...