I use a Kinivo ZX100 pocket speaker and it works very well.
Just a very good USB charger. Any nice headphones will work with it. This is a 3 3/4 inch player however. Very small.
I'm unsure what additional accessories you'd like to have. For charging, any standard USB to microUSB cable will work for connecting the device to your PC (to copy music over AND charge). You can also use your phone charger, provided it is the same type of cable as the afore mentioned.
Any 1/8" plug-equipped headphone set will work. You can also use most any Bluetooth headset with it. Keep in mind, there will be that one quirky, odd device that probably will work, maybe even SHOULD work, that simply won't work. :-)
JAM BLUETOOTH SPKRS OR A LITTLE CHEAPER IN PRICE EMATIC 8PC W/SPEAKER BOX. JAMS HAVE A REALLY GOOD SOUND THOUGH. ALSO HAVE THAT NEWER SCREEN PROCTOR APPLIED TO KEEP FROM MESSING UP SCREEN!