Amaze File Manager is a newer app comparatively speaking and it’s a pretty good. It’s open source and focuses on as lighter experience for those who just need to do some light file browsing. It features Material Design, SMB file sharing, a built-in app manager to uninstall apps, root explorer, and more. It managers to include the most important stuff without feeling bloated and it’s entirely free to use with no in-app purchases or advertisements (which I love it).
Get it from Play Store.