Notebook/applet computer and docking stations – easiest way to work efficiently from many places. You only need to maintain one computer, but can dock it conveniently to a nice keyboard and screen many places.
Powerbank – to re-charge if your phone or applet run out of power.
Earplugs with microphone – so you can work while you walk, drive or travel on airplanes, trains, etc. It enables you to give a Skype interview without the echo of your own voice.
Recording equipment – so you can create good social media posts. May consist of 1) selfie stick, 2) wireless microphone for your phone, 3) tripod for your phone, 4) cell phone holder for a car so you can attach the phone to the windscreen for selfie videos, and 5) steady-cam for stabilizing video takes when you are moving. You can buy all of this on, for instance, Amazon.com for a total of a couple of hundred dollars, max.
Mini-studio – if you want to create even more professional media. We could recommend, for instance, a Zoom H6 Six-Track Portable Recorder, which can be bought on Amazon.com for a few hundred dollars, perhaps combined with DT297 headsets, which cost a few hundred dollars each. The combination of a professional compact mobile recording equipment and headsets for, say, three participants in an interview, would cost around $1,000.