An accessory kit is a great way to get multiple accessories your system.
Always keep spare batteries handy and you won't get caught without power.
Add more interconnectivity options for your equipment.
Protect your audio from wind noise with a windscreen.
Get your mic closer to the sound source with a boompole.
Stabilize and isolate your mic from vibrations with a shockmount.
Additional brackets and rigs allow more convenient piggy-backing of devices.
Mount your microphone on a stand.