Foobar2000 is a well-known player from the Windows PC world, with a massive amount of plug-ins and customizable options. There is a mobile version of the player (currently free) that is a very simple design that works well for local library media, as well as having support to access local network media servers.
The design focus is on simplicity. The browse tree is text based and very straight-forward. The Now Playing screen is also quite simple, with large album art, a seek bar, Song/Artist/Album tags, and basic controls for play/pause, track up/down, shuffle, and repeat. There is a handy option to also display the next track, including a small thumbnail of the cover - this is a nice touch that other players don't often have.
The only gestures currently are swipe from the edge from the left of the Now Playing screen to get to the browser, or from the right of the browser screen to go back to Now Playing. And there is swiping up/down to scroll through the library lists. I do wish it would add Now Playing gesture controls, at least swipe left/right for track change, and perhaps tap to play/pause. Maybe this will come in future development.
There are minimal preference settings to adjust, mostly focused on some DSP options, Replaygain, and some view options for the library and browser. There is also an option for skinning the player, although there have been few packages distributed that I have found outside of what is in their forum.
But being simple in design doesn't take away from the strength of foobar2000 Mobile. As a cross-platform player, it performs remarkably well. Performance is very snappy, and it plays virtually any file format on any device.
As a free download on most mobile platforms, it can't hurt to give it a test drive. Since the topic is for Android players, I'll link to that page here.