Here are a few things I can think off. I am not an REI Employee...
REI has a checklist in their info pages.
Beware of taking extra stuff you do not need! It just adds weight and make the trip less pleasant. Just take one small knife between you. The only reason to carry a large knife is for cutting kindling but if fires are allowed you can generally make one without a heavy knife. Binoculars are optional so unless you have a particular interest they may just be dead weight
Appropriate footwear and layered clothing for the location and expected conditions. All synthetic or wool. No cotton. You don't need changes of clothes except underwear and something to keep clean and dry to sleep in.
Unless you are using campsites with pit toilets. Toilet trowel. Toilet paper and a way to pack it out...required in some places...desired everywhere. It does not decompose fast and if buried it tends to work it way back to the surface. No one wants to see your used toilet paper
A small first aid kit to deal with cuts and blisters, including sun and bug protection as necessary.
A topographic map of the area you will be hiking in. And a compass. If your smart phone is reliable you can cache maps on it if you will be sticking to well used trails that are not remote but make sure you have a way to keep your phone charged.
A trash compactor bag to line your backpack and keep you sleeping bag and sleep clothes dry. Most packs also need a pack cover to keep them from wetting out but you should use a liner bag whether or not you use a pack cover.
If you use inflatable sleeping pads, an appropriate puncture repair kit