I tried this on Google but couldn't find anything! Where can I find list of ESRI Applications Icons (not Map Symbols) representing the ESRI concepts like (Layer. Shapefile, Geodatabase, ....)?
If you're talking about the icons inside the application itself, you can find many of them by doing a search for
*.png in the application install directory. Of course what you may want to do with those icons will probably be covered by the terms of service you accept when you install the software.
If you're talking about the more 'marketing-like' icons you see in in Esri presentations, I don't think these are available anywhere. They are probably for Esri use only. As former Esri employee, I can say I never heard anyone talk about distributing these.