Assume that the future can change based on your actions, so any historical information that you bring along with you from the intervening 25 years may quickly drift out of the new realities history.
Edit: also assume that you can be given a healthy 21-year-old body if you want or take your previous self’s place.
Further, identification will be provided for you if you were not born at that time.
An entire offline copy of Wikipedia up to Jan 1 2024 on a tablet. Having all the world events up to that date available to consult at my fingertips, I could use it in so many ways.
Don’t forget a charger, otherwise you’ll be screwed for awhile
USB 1.1 was already around in 1999, USB 2.0 being released in 2001 with Mini-A/AB/B being available in 2001, and the standard Type-A as early as 1996.
Take one of those USB Type-A to USB-C and you’re good enough until circa-2008 when USB-C starts to get around
But the old USB chargers didn’t have high speed charging (2+amps) until much later. Most cell phones can’t charge effectively from the original 0.5A standard USB.
USB-C wasn’t designed until 2014. So yeah you’ll need a charging cable regardless
Even nowadays USB-C devices aren’t the de-facto yet(specially true in 3rd world countries like mine), Mini-B and Micro-C are still fairly common(tho really limited compared to USB-C), so depending on the devices being taken, it might not be that much of a trouble