There are hundreds of thousands of mobile accessories out there so this is going to be hard to just narrow it all done to five. Mobile accessories usually have different types like there is cases which generally protect the exterior of the phone, Bluetooth headsets which enable you to make calls without needing to hold the phone right next to your ear, car charger so you can keep on charging your phone whilst on the move, speakers so you can listen to your music on your phone anywhere you want and a desktop dock where you can charge and play your music in comfort and with some great sound quality.
Trying to find a Bluetooth headset sounds easy as you just think all of them will have the same features and sound quality but some have different signal quality, have noise cancellation, and some could have a better sound quality than others. The way to find the best Bluetooth headset is to see which features you really do need, as if you only need a Bluetooth headset for your car you don't really need one which has a huge signal range but you would need one which has better sound quality.
To find the best mobile phone case, you really should look at what kind of protection you want, you can have a case which can be quite light and flexible or you can have a mobile phone case which is quite heavy but offers a lot more protection than light case. Some cases can be made out of leather and offer a professional look and feel to it whilst some cases are just covered in coloured plastic materials, so obviously the more expensive and better looking ones will be ones made out of leather and cheap ones would be made out of plastic but would offer a more than satisfactory protection for your mobile phone.
A good in car charger would be a charger which can charge more than just your mobile; it can charge your friends mobiles as well. So a universal charger is always a great in car charger to have. An In car charger which is built by a well known brand is more than likely to last a lot more longer than an unknown brand. There has been chargers which just do not last long and lose their charge when using a unknown brand.
Speakers for a phone should have great sound quality, that is a must for any speakers, but because music has to be compressed to be able to be played on the phone, the sound quality originally won't be as good, this is why it is important to have quality speakers, so that you can improve the quality of sound. Usually you can find speakers with decent sound quality and can be found for a cheap price as well so; it will be easy finding the best speakers out there.
The best desktop dock would be a dock which has good quality speakers and can also charge the phone quite quickly. There are many docks like this out there some offering fantastic quality sound whilst others offer sound which is decent for a small room but are quite small docks. So the best desktop docks depends on where and what you will use them for.