How can I run an installed system application that doesn't appear in the app list?
Is there a way I can just run these apps instead?


If I were you and see such apps that are not in the Apps list, then I would take a look at AndroidManifest.xml inside the .apk (Extract by touch holding file under Es File Explorer &rarr; More &rarr;Open &rarr;ES Zip Viewer &rarr; Select .xml file and Extract, and view using Axel).

I would first try to see the activities registered under action.intent.action.MAIN e.g. for a file named Galaxy4.apk the associated activity name is .Galaxy4.

Relevant output from Axel:

&lt;activity 
    android:theme="@id/0x01030006" 
    android:label="@id/0x7F060000" 
    android:name=".Galaxy4" 
    android:launchMode="3"&gt;

   &lt;intent-filter&gt;
     &lt;action android:name="android.intent.action.MAIN"/&gt;
   &lt;/intent-filter&gt;
&lt;/activity&gt;


What's next to do? Fire up ADB or a terminal app and type:

am start -a android.intent.action.MAIN -n com.android.galaxy4/.Galaxy4


This command launched the app with its default activity. What's more? I realized that this .apk was actually a live wallpaper native to Android and can be accessed inside Wallpaper settings. Now it makes sense why it isn't needed in the Apps list.

Your case probably would differ and so, type am to see various parameters that it has. You may also take a look here and here.