Stuff I recommend – Amazon

List of basic tools I highly recommend and use regularly. I own all of these, and have tested them extensively.

A long USB cable. They make life so much easier.
Micro USB Cable, Sunnest Samsung Charger 3Pack 10Feet Braided High Speed USB 2.0 A Male to Micro B Charging Cord Universal for HTC, Motorola, Nokia, Android, and More (Black)

A high output dual port charger.
USB Wall Charger Dual Port 4.8A/24W High Output (White Limefuel L48WCW) Foldable Portable Rapid Travel Charger for iPhone 6, 6+, 5S, 5C, 5, 4S, 4; iPad 5, Air, Mini; iPod Touch, Nano; Samsung Galaxy S4, S3, S2, Galaxy Note; Kindle; LG G2; PS 4; Nexus 5, 7, 10; Motorola Droid Razr Maxx; Blackberry; Nook Color; Bluetooth Speakers & Headsets; Nokia Lumia 2520; HTC One X V S

A portable USB charger. Phones take power, lots of power. I like to read on my phone. I also used to play Ingress. And go on long hikes and take lots of pictures. This one has been good to me for years.
cheero Power Plus 3 10050mAh – Dual USB and Super compact portable power bank for iPhone / iPad / Android / Xperia / Galaxy / smartphones / tablets / Wi-Fi routers [AUTO-IC Function] CHE-072 Black

Male to Female stereo cable – use with my headphones, so I have a quick disconnect as well as a longer range. If it gets caught, or I trip, or a need to move it, the connect breaks at the junction, instead of ripping the headphones off my head.
AmazonBasics 3.5mm Male to Female Stereo Audio Cable – 12 Feet (3.66 Meters)

Cheap bluetooth headsets. I buy them in multiples at a time, because I lose them, or leave them in a pocket. At less than $15.00, I don’t feel bad, like I would if my $100.00 + ones went in the washing machine by mistake. I have enough to have a couple in my car, and a couple in my office.
Samsung HM1350 Wireless Hands Free Bluetooth Headset- Black Flat

Replacement ear hooks for your bluetooth. The cheap plastic ones always break. You’ll need to keep some spares around.
10 No-break Replacement Ear Hook Compatibility: Samsung HM6000 HM1300 HM1900 for Bluetooth Headsets

I got this only recently, after I moved to my new place. The power was really spotty for the first year, and went out a lot. This guy saved me from lost work at least 20 times. It is big enough to run my two development machines, and two monitors, for at least 20 minutes. Plenty of time to save everything. But mostly, I just needed it in case a breaker tripped. Because it is inline, it also protects my hardware from over/under voltages.
APC Smart-UPS 1000VA UPS Battery Backup with Pure Sine Wave Output (SMC1500)

Replacement cable for Sennheiser headphones. I use these short ones, and connect them to a longer cable on my machines, for quick changing, as well as safety(the connection will disconnect before I can trip on them)
1.2m Replacement Audio upgrade Cable For Sennheiser HD598 HD558 HD518 Headphones

Big, around the ear, headphones. They don’t touch my ears, meaning I don’t get sore ears after hours of wearing them. Either open or closed can. These are open, meaning they allow some air in, and some sound from the outside gets in, and the phones can be heard from outside even when worn.
Sennheiser HD 598 Over-Ear Headphones – Ivory

These are closed. They don’t let outside sound in, and the headphone sounds don’t get out. I have both, they are both excellent. I think I prefer the open ones more, but that’s because I don’t care about the sound bothering people when I wear them while I code or game.
Sennheiser HD 598 Cs Closed Back Headphone

Dual layer cell phone case. I’ve used Incipio hard shell cases for years. Dropped them numerous times. Never had an issue. I’ve had them for several generations of Galaxy and Nexus, they’ve all been good. Get one. For Galaxy S8
Samsung Galaxy S7 case, Incipio DualPro, Hard Shell Case with Impact-Absorbing Core Shock-Absorbing Impact-Resistant Dual-Layer Cover – Black/Black

Or Iphone

iPhone 6S Case, Incipio DualPro Case [Shock Absorbing] Cover fits both Apple iPhone 6, iPhone 6S – Black/Black