Anker MagGo Power Bank (ultracienki, 10K, MagSafe)

Tossed this in my carry-on for a week in Iceland and it charged my phone almost three full times before needing a recharge itself. The slim profile means it slides into a jacket pocket without that bulky brick feel. Genuinely the best travel gadget I've picked up this year.

The magnet snaps on solid and I can text one-handed while it's charging, which is the whole reason I wanted a MagSafe bank. At 10K it got my phone through a full day of sightseeing plus an evening of photos. It's slim enough to slip in my jacket pocket without a bulge.

Took this on a week-long trip and never once worried about my phone dying during long sightseeing days. It's slim enough to slip into my jacket pocket while still charging, and the magnet holds my phone securely without a case.