The "Simple Mobile Tools" family of apps by Tibor Kaputa (distinctive for their orange icons) are available on F-Droid and are superb. A great fusion of minimalism and functionality, they've never let me down.
+1 for Simple Mobile Tools. My newest phone didn't contain much vendor installed apps, so I was looking for nice and preferably open source replacements for the basic apps like gallery, and simple mobile tools solved all my problem.
also a ton more functional(options) than the stock equivalent and even appearance. though for music i like vanilla player it's UI may be dated looking but lots of functions that i like.
https://github.com/simplemobiletools
https://simplemobiletools.github.io/