DiskDigger is a free application that allows you to find and recover deleted photos on Android without root access (but it can make the result can be better). It is suitable in simple cases and in cases when you want to find exactly the photos (there is a paid version of the program that allows you to restore other types of files).

GT Recovery for Android

The next free program that can be effective free android data recovery for modern Android devices is GT Recovery application, which is installed on the phone itself and scans the internal memory of the phone or tablet.
Android application for GT data recovery
I have not tested the application (due to difficulties with obtaining root rights on the device), but reviews on the Play Market say that GT Recovery for Android quite successfully copes with android picture recovery, videos and other data, allowing you to return at least some of them.
An important condition to use the application (so it can scan the internal memory for recovery) is the presence of root access, which you can get by finding the appropriate instructions for your model of Android device or with a simple free program.

EASEUS Mobisaver for Android free.

EASEUS Mobisaver for Android free is a program for free android photo recovery and data recovery on Android phones and tablets, very similar to the first of the utilities discussed, but allows you not only to look at what is available for recovery, but also to save these files.
Android data recovery in Easeus Mobisaver free
However, unlike Dr.Fone, Mobisaver for Android requires that you first get root access on your device yourself. And only then the program will be able to search for deleted files on your Android.
Learn more about using the program and downloading free photo recovery software for android Easeus Mobisaver.

What should you do if you are unable to recover deleted files on Android device with Disk Drill?
As mentioned above, the probability of successful recovery of data and files on an Android device from internal memory is lower than the same procedure for memory cards, flash drives and other drives (which are defined as a drive in Windows and other OS).

It is possible that none of the proposed methods will help you. In this case, I recommend you try the following:
Go to photos.google.com using the login credentials of an account on your Android device. You may find that the photos you want to recover are synchronized with your account and you will find them intact.
If you need to restore your contacts, go to contacts.google.com -there is a chance that there you will find all your contacts from your phone (however, mixed with those with whom you communicated by e-mail).
I hope some of them will be useful to you. Well, in the future you should try to sync your important data with Google or other cloud android recovery software, like OneDrive.

7-data Android Recovery

When I wrote about another program from the 7-Data Disk Drill Android data recovery, which allows you to restore files from a flash drive or hard drive, I noticed that their site has a version of the program designed to restore data from the internal memory of Android or inserted into the phone (tablet) micro SD memory card. I considered it to be a good topic for one of the following articles.
Download Android Recovery from the official site 7datarecovery.com/android-data…. Thus, at this point the program is completely free. Update: the comments reported that it is no longer free.
The installation does not take much time — just click on the “Next” button and agree with everything, the program does not install anything extraneous, so you shouldn’t worry.

Once connected, click on the “Next” button in the main window of the Android Recovery program, and you will see a list of drives in your Android device — it can only be internal memory or internal memory and memory card. Select the desired vault and click on the “Next” button.

Files and folders available for recovery
When the file search process is complete, the folder structure will be displayed so that it can be found. You can see its content and use the preview function if these are photos, music or documents.
Once you have selected the files you want to recover, click on the “Save” button and save them to your computer. Important note: do not save the files to the same media from which you recovered the data.