Here is a spattering of things I have found useful in my travels.
The backpack I currently use. Fits everything I need for about a week of travel. Overhead airline sized and smartly laid out. I really like this bag.
Hydroflask Stainless Steel insulated waterbottle. These things are amazing. They keep cold things cold, or hot things hot for a long time. Stainless steel, so easy to really clean. I have a few sizes.
You will also need a bottle brush to keep the thing clean. This one works well.
Hammock – No just for laying around anymore
Whoopie Slings – to attach hammock to tree straps
Tree Straps – Don’t be a jerk and use rope on trees
Carabiners – to clip it all together
Rain Fly – for staying dry
Bug Net – Stay safe from the mosquitoes
Lightweight slip-on shoes. I don’t mind if I wreck them
USB Bank Charger – Why carry all those extra cables
Helps me relax and get to sleep in different time zones. Doesn’t leave me groggy like dyphenhydramine.