Symphony github link It has nice UI, very polished and have folder view and lyrics support But there’s a major catch, unlike other players, you will need to keep the app open in background
Gramophone github link Also have a nice ui, but not very polished. Absolutely usable. Have folder view and lyrics support
As an Android developer and as an user, I would prefer a standard and tested set of rules rather than reinventing everything. I know everyone have different taste, but I would trust an expert (someone who designed and defined Material rules) rather than my own judgement. Don’t have an eye of a designer