Hey there, welcome.
I don't really like to take too much stuff when I fish. Couple boxes of flies.
I like to have a nice fixed blade knife for "you never know when you'll need a knife" moments. I have a stainless Mora.
Piece of rubber inner tube to straighten your leader. Some back up leaders, New tippet material. Few split shots. No old leaders, new leaders every year. Plastic bag, bug spray, nippers, stats, floatants, water. Anything else for me becomes a burden. Maybe some trail mix or nut bar.