How to Restore Mobile Deleted Data without Backup?

Is it possible to restore deleted data on an Android phone without backup?

When files are deleted from your Android phone, the data of the deleted files are not wiped from the Android phone. So the files are still on the phone. Hence, technically it is possible to restore deleted data on an Android phone, even without backup.
It is actually quite funny that people tell you different ways to recover deleted data from an Android device without root and at the same time they are recommending software/apps that do not work without the root access. I’m not saying that all these software don’t work they DO but most of them work on the rooted Android devices.
To get back deleted files from Android phone, you need professional data recovery software (mostly not free - the free versions come with very limited features like some only show your deleted files but don't recover these, etc).

Some Free / Paid Tools to Restore Mobile Deleted Data

To name a few, these are some of the Softwares that help you Recover / Restore Mobile Deleted Data (There are many many more such Softwares).
Dr.Fone Android Data Recovery (Paid) Works with Rooted Devices
Asoftech Data Recovery (Free)
Android Data Recovery Android/iOS Devices (Paid - Comes with Free Trial)
iReparo Android Data Recovery (Paid - Comes with Free Trial)
Samsung Data Recover (Android Particularly for Samsung Devices) (Paid - Comes with Free Trial)
MobiKin Doctor for Android (Paid - Comes with Free Trial)
Gihosoft Android Data Recovery (Paid - Comes with Free Trial)

How to USE these Tools?

These are the steps that are usually followed to recover deleted data:

1. Enabled USB debugging on your Smartphone (by Going to Setting in enabling Developers Options) and connected it to my computer using the USB cable.

See Also: Developer Options: Know Everything

2. Select the files you want to recover and click “Next” button to scan your Android device.

3. After reviewing the deleted files click “Recover” button to recover the files that you selected in the previous step.

Restore Mobile Deleted Data from Google Drive

I know that this question is about recovering data without a backup but in case you want to recover deleted data on Android without using any paid software or service then your only bet is Google Drive. If the “Google Drive” backup option is turned on your device then there are some chances that you can restore some files like apps, contacts, calendars, call history, device settings to your Android device.

If you’re using Pixel or Nexus devices running Android 6.0 or above then you can also recover text messages (SMS), photos and videos from the Google Drive.
There are two methods that you can try to restore deleted data from Google Drive:

Method 1: Remove the Google account from your Android device and then add it again. When you’ll add the account back you will be asked to sync the data from the Google Drive to your Android. Select “YES” and you would probably see some deleted items like apps, contacts, calendars, call history back on your Android device.

Method 2: If you have two Android devices, then you can add your Google account to the second Android device and restore the deleted files from the backup.

See Also: Manage & restore your device backups to Google Drive

Important Notes

• You will be able to recover the deleted files from Google Drive only if you enabled this option before you lost or you deleted your Android data.
• To prevent such incidents happening again, you can download the apps like ‘Dumpster’, so that the deleted files first go to the recycle bin of the app and you can restore them from there in case you need them back.
• The deleted data are not yet being overwritten, which requires you stop using your phone after data losing.
• If you have a 'Rooted Devices', chances are great to Recover your data.