Clothing is always your first item of survival equipment
Waterproof Oilskin Leather Raincloaks... Clothing is always your first item of survival equipment, as you are almost never without it. The above item is the 13th-Century equivalent of the US Army (and other countries' militarys') poncho and liner... A waterproof outer cloak with drawstrings at waist and hood. A button-in wool liner, for warmth (which can also be used as the infamous towel or blanket). Grommets along the cloak's edges allow it to be staked down, and two, buttoned together face-to-face, make a two-man tent. Either can be used independently as rainfly, sunshade, etc. Pre-attach two feet or so of tough cord to each grommet, and roll the cords together, to keep them out of your way. When shelter is needed, use some sticks as stakes, and you're all ready.
Bootlaces should be replaced by (or supplemented with) slings. A few bullets or rocks gives you an impromptu missile weapon. In fact, anything rolled and tied (blankets, bedrolls, towels, etc.) should be tied off with slings. Including long hair (if your PC has it). Slings are free, in D&D. At higher levels, Masterwork slings remove the -1 penalty for using rocks as ammunition.
Bandannas. Bandages, slings, tournequits, water-strainers, ties, semaphore flags, head-coverings, handkerchiefs, etc. Cost about two silver pieces, in the real world. A suit of clothing can include these. 22 x 22" or so.
Belts/Girdles. Every suit of clothes should include at least one, solid leather, with a sturdy buckle. There's more than 3' of sturdy rope, for most PCs, and it can also do most of what the bandanna can, as well (although not all). Girdles often include pockets, as well. Can be used as a sling, or an impromptu entangle/trip or bludgeoning attack, among other uses.
Stocking Caps/Gloves/Socks. All usable to help keep you warm in cold weather, but also as sacks for coins, etc.
Shemagh. The PHB states that, if the player desires, a suit of Explorer's Clothes can contain a scarf. The Shemagh is the long one worn by desert ("Raghead") people to keep the sun/wind/dust out of their eyes, ears, noses, and mouths. It is also quite warm in cold weather, and its great length can be used as impromptu rope (roughly 6'). It costs less than one gold piece, and is about 44 x 44".
Jacket/Vest. Mainly used to keep you warm, or carry more gear. Not too many other uses that I'm aware of.
Beltpouches. The well-dressed adventurer needs several, to tote all those spell components, potions, and various missile weapons that are needed at a moment's notice.
Pants. Impromptu flotation device. Incorporate some drawstring cords at the bottom. In them keep the small, light items that you can't afford to lose... Flint & steel, chalk, needles, fishhooks, signal whistle, candles, etc. Put duplicates in your pack, saddlebags, pouches, and necklace, as you rise in level (and can afford them).
Shirt. Drawstring waist, lots of pockets. Pack them with useful gear, too, as you're rarely without one. "Lapel daggers" are just one such idea.
Survival Necklace. Woven strands of steel wire, woven about two metal rings at the ends, forming a ringsaw. Can be used to cut wood for fires or shelters. Through the rings attach a small piece of beaded chain (to keep the saw from hanging you, if it gets snagged on your way down a cliff or tree)! To the chain attach two small pieces of metal, one of which is mirror polished, for use as a signal mirror, the other of which is sharpened for use as an impromptu knife. Protective cloth "sheaths" can be added, if you like. Between them hang a signal whistle, and a small wooden box, made waterproof with wax. Inside, insert the needles, fishhooks, line, sinkers, float, candles, flint, steel, and some small strips of dry, waxed wood (perhaps a few tindertwigs). This "Tinderbox" will make starting a fire in the rain easy! To this, add a compass, if your GM allows (about one gold piece, for a cheaper model). If not, see if you can get a magnetic lodestone (which does about the same thing). If you want, counterbalance the box's weight with a dagger & sheath hung on the rear, and include a sharpening stone pocket on the sheath.
My PC is a woodsman, so I always include a handaxe and longknife. YMMV. If you go for them, make sure the handaxe is backed by a hammerhead, and is throwable. Make sure the longknife is throwable, and some may have screw-in pitons and a rope-attachment point for use as a grapnel. If so, make sure the sheath holds these, as well as the sharpening stone. Many also have hollow handles for storing a few matches (Firesticks) and some fishing gear.
In any case, don't forget some string for fishing line, and tieing things together (like when building a shelter). String is more useful than twine (easier to fish/sew with).
Now in the REAL world, you'd want a spool of snare wire, as well... but in D&D, you can't really set snares. It does have other uses, though. A roll of four 40' lengths would cost about five coppers. (See the post on Tripwires & Alarms, for other uses!)
All of these items have a wealth of uses. Of course, I recommend adding armor, weapons, perhaps a shield, a pack, some rope, a bedroll, etc., etc.... Clothing is just your first piece of survival gear!
lights the darness, keeps foes at bay, signals over great distances, sets fire to things, the tool of the angry mob, can be used as a weapon...
