Mundane Equipment for 3.5
Most GMs won't be sticklers for the mundane equipment because the focus is on the game and playing. However, if your game revolves around resource management, then a list is always good.
Basics: Backpack and belt pouches for holding stuff.
Bottles or waterskins for holding potable fluid or collecting new fluids
Rope (Silk is best for weight) is good for rappelling and climbing, rigging up traps, or just tying up captives.
10' Pole is hilarious, not practical, but still recommended to 'find traps'.
A mess kit so you can cook and eat a meal in a reasonable manner (utensils are recommended)
Pitons or spikes to use with rope or prop open doors, wedge open gates, or spike them closed.
Caltrops and marbles are good for impeding ground movement
Torches are cheap, Ioun torches are relatively new but great for light. Lanterns, especially hooded were the go-to back in the day. Continual light cast on a rock or coin is handy to have in a pinch. Toss it in a lantern and no need to purchase oil.
Bedroll and tent are optional but sleeping is handy. You can wrap yourself in a cloak/cape and rest your head on the backpack. Sleep rules only care about wearing armor, not about how you sleep.
Depending on your profession or skills tools can make life easier:
Lock picks for opening locks, various crafts gain bonuses for having tools. Bards usually have a musical instrument. Scroll cases for maps or actual scrolls, again optional.
Appropriate clothes - Cold Weather, Warm Weather, fashionable or disguise worthy is also optional. That's more for flavor unless you play a campaign built around extreme weather.
That covers 90% of what most adventurers will carry. Anything else is either very specific or for a theme.
I've seen players have wheelbarrows, sometimes shovels and picks, in anticipation of hauling out a lot of loot. Seriously, handy haversacks and bags of holding are your best friend and make it easier when dungeon delving than a wheelbarrow.
Most games once past the first couple of levels never focused on equipment and just moved to the adventure. But maybe you get the bookkeeping GM who cares about resource management to the mundane level. Once you can fly, make dimensional pockets, and have force discs follow you around, mundane equipment matters less and less.
Hope that helps.