Top Alternatives to Nimble Commander

Total Commander is a Windows based file management program with the good plugin system.

Cyberduck is an open source client for FTP and SFTP, WebDAV, and cloud storage.

Double Commander is a cross platform open source file manager with two panels side by side.

Midnight Commander is a visual file manager, licensed under GNU General Public License and therefore qualifies as Free Software.

Far Manager is a program for managing files and archives in Windows operating systems.

Commander One is a dual pane file manager for macOS, created entirely in Swift.

Transmit is an FTP client for OS X. Developed by Panic, Transmit is shareware.

muCommander is a lightweight, open-source, cross-platform file manager that will run on any operating system supporting Java.

Krusader is an advanced orthodox file manager for KDE and other desktops in the Unix.

TotalFinder is a plugin for Finder.app which adds tabs like those in Google Chrome, dual panels similar to TotalCommander, and other improvements.

ForkLift is a file transfer software, It allows you to transfer files using FTP, SFTP, FXP, WebDAV, Amazon S3 and even Bluetooth.

XtraFinder adds Tabs and features to Mac Finder.

Path Finder (SNAX) is a Macintosh file browser.

Finder is the default file manager and graphical user interface shell used on all Mac.

fman is a dual-pane file manager for Windows, macOS and Linux.