12. Mains battery charger
This is perhaps the oddest item in the dozen and in my case is somewhat manufacturer-specific. As someone with a fair number of Nokia smartphones on the go, and a fair number of batteries that are largely compatible, I find it very useful to be able to charge batteries 'out of the device', so that I know that all my spares really are fully charged when sat on the desk. It's also handy when one's partner says 'oh, my phone's nearly out of power' two minutes before setting 
off on a journey - "No problem, here's a fully charged battery, pop that in" etc. I use the now discontinued Momax charger shown above, but there are equivalents on eBay and Amazon for HTC and other makes of smartphone battery, so do your research and you'll find something. [PS. Following the comments below, seems like the one to go for is the official Nokia DT-33 charger. Watch this space for a review....]
11. Car dual USB port adapter
These days one is faced with an ever increasing number of things which need charging in the car and there are two options: split the 12V socket into multiple sockets and then buy/bring each device's 12V charger cable, or split the 12V socket into multiple USB outputs and then use the standard charging cables that you already own. I take the latter approach and find an adapter like this very useful. Anyone know of a triple USB adapter?
10. MicroSIM adapter
Sadly different sized SIM cards are now a fact of life. And, yes, a curse on all the parties involved's houses. I refuse to touch nanoSIM, but at least half my handsets are now microSIM and yet I also want to switch to phones with full size SIM slots every once in a while. The danger is that most cheap plastic adapters leave protruding edges, which then catch on some SIM card slots and can damage the delicate contacts. After some experimenting, David Gilson and I have come up with a winner, characterised by an open back, yet with small diagonal supports in the corners. These are sold by quite a few sellers (e.g. here) and we usually look for the phrase 'German patented' in the item description.
9. Silicone/rubber case
One fact of life for many smartphones (think Nokia N8, Lumia 800/900, iPhone, etc) is that their sleek looks come at a price - they're very slippery. I know, I know, it's a shame to cover up said looks, but when you're out and about at least, use your phone in a silicone or rubber case - they cost only a few pounds or Euros on eBay and will make darn sure that you don't drop your pride and joy. For example, my Nokia Lumia 800 came with an official rubber sleeve that fits like a glove and here's my review of the official silicone case for the N8, back in the day.
8. Bluetooth stereo headset
Yes, I cover a wired headset below, but if you're happy charging an extra module and don't mind a tiny bit of reduction in music quality then a decent Bluetooth stereo headset is the way to go. I prefer the type that has the full multimedia controls in a pod that clips to a lapel or short pocket, and then into these I plug the in-ear buds of my choice - I use the Nokia BH-214, shown here, still available at £25, which needs charging only about once a week, even with several hours listening a day. There are many different Bluetooth stereo options these days though, including many with media controls built onto the earpieces, so browse around.
7. Integral charger no. 1
Later in this top 10 there's a battery/charger, but it's encumbered by coming with all sorts of bits - cable tips, connecting cables and adapters, all of which can get lost far too easily. One solution is to have the cables and connectors integral to the battery, i.e. there's nothing whatsoever to lose. This is exemplified by one of my favourite little gadgets, the Nokia DC-11K, which contains a 1500mAh battery and tethered, flying leads for both Nokia 2mm and (more appropriately, for many modern phones) microUSB output. Each of the short cables tucks neatly into the body of the battery, making sure nothing gets damaged. See here for my review of the previous DC-11 (currently a real bargain on Amazon at under £10) - the only real downside in late 2012 is that the input to charge the DC-11K has to be of the 2mm rather than microUSB variety - fine for Nokia die-hards but annoying for others.
(the DC-11, the DC-11K's predecessor, being charged and simultaneously charging two other phones...!)
6. Integral charger no. 2!
Which is where my second integral charger comes in. Proporta's diminutive Pocket Power is strictly microUSB in and microUSB out, with the output lead stored neatly in a recess in the body of the battery. Overall capacity is small at 680mAh, but then this is meant for keeping in a wallet (hence the credit card form factor) and providing an emergency half-charge for when you're caught short, as it were. A terrific idea - everyone should have one in their wallet - empirical evidence points to needing to top it up every couple of months in such a use case. See here for my review.
5. Slimline belt case
Most phone-sized smartphones of the last 3 years have fitted happily in the PDair Leather Case for the N8 - don't be put off by the last bit of the name, this has also fitted just about every Nokia smartphone I've tried, including the newer Lumia 710 and 800. There are similar cases for larger (and smaller) phones though.
4. Nokia Play 360
Although high in my top 10, I can't really afford these. And I use the plural because these Nokia MD-50W 'Play 360' Bluetooth speakers have the unique facility whereby if you pair them together, they turn into rendering full stereo. But you do need two of them, so it works out quite expensive at around £100 each. You can tap them to pair and then tap them again to start playing (via NFC), they sound great and one of my favourite features is that they're powered from a standard phone battery, so you can replace this after a year or so and get full capacity again. See also my full review.
3. Multimedia headset
As featured here, I prefer the old (OMTP-compatible) Nokia AD-54, with the in-ear buds of my choice, giving full control of my music and podcasts without even looking, with the phone in my pocket, but non-Symbian handsets will likely as not use the rival AHJ (American Headphone Jack) standard, first seen in the likes of the iPhone and supported by most Android and Windows Phone handsets. AHJ headsets are based more around multiple presses of one central button, but you can buy AHJ multimedia headsets with multiple buttons, happily.
2. Turbocharger 7000
This is the largest pocket battery that Proporta do and I swear by it - the Turbocharger 7000 (£5 off here - disclaimer: this is an affiliate page, so I get a few pennies too...), in its velvet bag and with all the various tips, the mains USB adapter and 12V adapter, goes with me on every trip. Standalone, it gives me about five full charges of my Nokia 808 or about three full charges of my Galaxy Nexus. And then I can be topping up the Turbocharger itself from mains sockets that are convenient, as and when. Essentially, it means that I never have to remember the chargers for anything. Whatever* I bring along by way of phones and gadgets, there will be a cable tip for it for the Turbocharger. See also my full review of this accessory.
(*iPhone 5 owners need not apply, for obvious reasons....!)
(shown without the mains-to-USB and 12V-to-USB adapters that I bring along too.... 8-) )
1. Mini desktop phone stand
It's tiny, it's trivial, it's cheap - and I use it every day. It's a simple clamshell widget that fits in the smallest corner of the smallest pocket and yet which securely holds any smartphone up at the right angle to watch TV or video clips or YouTube. The inside surfaces are nicely grippy and this system seems a lto more secure than the Nokia DT-29 I used to use three years ago (it came in the box with the Nokia 5800!) I honestly can't remember where I got mine from, but I did find this for just under £3 on Amazon. And, I'm sure, from many other establishments!
