When you unpack your new keyboard, you'll have the basic accessories you need to operate and play it. But adding other cool accessories can improve and enhance your keyboard playing experience; some accessories are more essential than others.
Here are the must-haves:
Keyboard stand: Only home digital pianos come with stands or legs built-in. For all the others, you'll need to put it on something. The cheapest and most common stand is called an X-stand; it's a simple X-cross brace made from metal tubing. X-stands aren't very sturdy and can wobble, bounce, and even fail. Better choices include anything with four legs or a more-robust frame design.
Damper/sustain pedal: This pedal keeps notes sounding when you let go of a key. It looks like the pedals found on an acoustic piano and is highly recommended.
Momentary switch: You can use this flat pedal as a sustain pedal, though this option isn't as desirable. It is cheaper than a damper pedal, so it can be a first step until you save up for the better pedal. Many keyboards can use this type of pedal as a switch to turn on/off effects or parameters, move up or down to the next program, change the speed of a rotary speaker effect for organ, and other useful functions. Not all keyboards have a second pedal input.
The following options are great to add to your arsenal as you improve your play:
Sweep/CV/expression pedal: This foot-controlled pedal pivots forward and back; you can use it to control volume and to sweep through the range of a parameter (like filter cutoff), among other things. It's a great addition if your keyboard supports it.
Dust (soft) cover: A soft cover keeps dust and dirt from getting in between the keys and into knobs and sliders. It's good for home use.
Soft case: These padded bags/cases are good for lighter keyboards that you have to be careful when moving around. Be sure it has strong/comfortable handles and straps to carry and has some reinforcement in the padding.
Hard (road) case: This case is for larger keyboards or any gear that you're going to move around a lot and may tack other things onto while in transit. Look for strong locks and handles; if your instrument is heavy, try to get a case with wheels on one end for easier moving.
Bench/stool: You have to sit on something! Good benches are height adjustable, padded, and sturdy. They're better than sitting on a regular chair or folding chair, which can suffice in a pinch.
Music stand: Some keyboards come with a music rest, which is a holder that slips into the back of the keyboard to hold music, songbooks, and so on. Not all offer this option, so you can buy a metal music stand to place on the floor behind the keyboard. Don't get the cheap, flimsy folding stand type; they're not worth the savings.
iPad holder: Many musicians are using their Apple iPads to read music scores from; if you don't have a music rest on your keyboard, you'll want a way to hold the tablet up. You can place it on a music stand, but dedicated tablet holders are available, many of which clip onto a mic stand.
USB MIDI control surfaces: If you wish your keyboard had more knobs, sliders, or drum pads, you may be able to add them by using a compact USB control surface. Check to be sure whether one can be connected directly to your keyboard or needs to be used within a computer setup.
Headphones: For private practice and close concentration, headphones are essential. Be sure to get good-quality over-the-ear or on-the-ear designs. Cheap earbuds aren't recommended.
Keyboard amplifier/speakers: You can always listen to your keyboard through headphones, but when you want to rock out in the open air, you'll need speakers of some sort. If your keyboard doesn't come with onboard speakers you have a few choices: Plug into your home stereo or computer speakers, or purchase a keyboard amplifier or powered speakers of some sort. Keyboard sound better in stereo, so be sure to get a stereo amp or two powered speakers.
iPad connections: If you want the option of connecting to your iPad, you need either Apple's iPad Camera Connection Kit or Lightning to USB Camera Adapter cable (better than the plug version).