Hi ​@ohashkii 
You Should be able to create a User Parameter in your Workbench. After publishing you will see the default value if you look at the Workbench in FME Flow. If you clear the default value you will then get the option of selecting a gdb location. Is this what you meant?
I hope that helps! Good Luck!
 

Hi,

What I meat if I can create a published parameter for the feature class inside the gdb file. I want to choose the feature classes (MH,Pipe,Plots or other feature classes within the gdb).

thanks for your reply.

Hi ​@ohashkii 

 

If you import the layer names from the geodatabase you will get a dropdown list.
Run will give the user the dropdown option.
 

This is static. If you need dynamic (it changes all the type) then you would have to explore a Scripted Selection.
Dynamic choices using Scripted Selection - FME Packages SDK Guide

I have been trying to set something like this up for a while now. Future versions of Flow might have parameter values that we can work with while passing between workbenches.
Scripted Selection List Choice or Dropdown Form vs Flow | Community
This was my question on the subject.

Hope that helps. Good Luck!