MobileFileSearch is a freeware tool for Windows operating system that allows you to easily search files inside an Android device plugged to USB port on your computer. You can search files by their size, their created time, their modified time, or their name (using wildcard). MobileFileSearch is a standalone .exe file that you can put in any folder you want and run it without need of any installation process.

In order to search files on Android device with MobileFileSearch, you have to plug your Android device to a USB port on your computer.
After plugging the device to the USB port, you may need to select 'File Transfer' USB connection in your Android Device, like in the following screenshot:

Assuming that Windows operating system identifies your Android device correctly, you should see the device in Windows Explorer:

After your Android device is connected properly to your computer, here's how to search files on your device with MobileFileSearch:

1. Run MobileFileSearch.exe
2. In the 'Search Options' window - choose the desired search configuration to search your Android device. In the example below, I chose to search .mp4 files (*.mp4 in Wildcards field) that have been created in the last 7 days and their size is at least 50 MB:

   

3. Click the 'Start Search' button, and MobileFileSearch will start searching your Android device.
4. After the search process is finished, you should see the list of all found files, like in the following screenshot:

   

5. You can now select one or more files (You can press Ctrl+A to select all files), and then copy them to a folder on your system (Choose the 'Copy Selected Files To' menu item or press F8) or delete them (File -> Delete Selected Files or press Ctrl+Delete). You can also export the files list into comma-delimited/tab-delimited/XML/HTML/JSON file by using the 'Export Selected Items' option.

MobileFileSearch also allows you to activate the Android files search from command-line and then export the search result to a file. For example, the following command searches .mp4 files that have been created in the last week and their size is at least 50 MB and then exports the search result to comma-delimited file:
MobileFileSearch .exe /CreatedTime.FindMode 6 /CreatedTime.LastXX 7 /UseFromSize 1 /FromSize 50 /FromSizeUnit 3 /Wildcard "*.mp4" /sort "File Size" /scomma "c:\files\android-large-mp4-last-week.csv"

You can get more information about using the command-line options in MobileFileSearch Web page.