What is the best completely free software to recover deleted files and folders?

Here are the best free data recovery softwares:
1. Stellar Free Data Recovery

Stellar provides a free version that allows for recovering only 1 GB of data.

Supports a wide variety of file types (photos, videos, email files, documents) and storage media: HDD, SSD, USB, SD cards.

You can preview recoverable files before saving so that you don’t waste space.

Limitations:

In the free version, only 1GB of data can be recovered.

The free version doesn’t come with technical support.

2. TestDisk + PhotoRec

TestDisk: powerful, free, and open-source. It’s great for recovering lost partitions and fixing file systems.

PhotoRec: Scans by signature, supports many file formats.

Pros: Unlimited recovery – no real data limit; works on Windows/Mac/Linux.

Cons: Command-line interface, particularly PhotoRec; may not preserve folder structure or file names.

3. DMDE (Free Edition)

A disk editor + recovery tool.

The free version can recover up to 4000 files per folder in a single run.

Supports many file systems (NTFS, FAT, EXT, etc.) and is able to keep the folder structure intact.

Limitations include that the “free” cap is by number of files, not overall data size; and the interface is somewhat technical.

4. Windows File Recovery (winfr)

Official Microsoft command-line tool for Windows. Fully free. Limitations: CLI-based, so not very user-friendly, especially for beginners. Recuva (Free Edition) Very easy-to-use GUI. Good for “simple” data loss: recently deleted files, emptied recycle bin, USB drives. Limitations: May not work quite as well on drives that are deeply corrupted or formatted; fewer advanced settings than something like TestDisk.