Well, let's see for the woods, I suppose. Who that has forests is interested in what wood?
Laenar Wood: in Dragon Annual 5, mentioned as a 'light wood' for arrows. Possibly replaceable with Darkwood.
Bluewood: Unapproachable East, an alchemically treated wood that is as hard as steel and half the weight of normal wood. The wood is implied to be something exotic, but seems to have the same properties as Darkwood. Thus, possibly replaceable with Darkwood with alchemical treatment, which is Darkleaf (see below, though that can't be used to make weapons). Can explicitly be used in weapons.
Bronzewood: First in Arms & Equipment Guide, then in Eberron Campaign Setting. Basically the Wood version of iron. Can presumably be used to make wooden swords that are just as good as steel. IE, implied to be able to be used in weapons. Maybe can be folded into Coldwood, or vice versa.
Darkleaf: Darkwood & Alchemically Treated Darkwood Leaves. Act kind of like mithral, though a bit weaker than the version of mithril that Duskwood is, albeit implied to be more versatile (ie, more armor types). Good for Armors. First in Arms & Equipment Guide, most recently in Eberron Campaign Setting.
Leafweave: Alchemically treated Leaves. Acts like Leather. Races of the Wild Originally in Arms & Equipment Guide and Dragon Magazine 279. Most recently in Eberron Campaign Setting.
Darkwood: DMG, half the weight of normal wooden items. Possibly the basis of several other 'wood' items from various books.
Serrenwood: Book of Exalted Deeds. An automatically ghost touch wood, used especially in bows, with DM ruling, maybe could be used elsewhere. Useful if you don't want to make things +2 to make thim able to affect ghosts.
Duskwood: Magic of Faerun. The most explicitly, without alchemical treatment, wood that acts in most ways like Mithral. Can explicitly be used in weapons. Unfortunately, is described as hard to work, ie, especially compared to the other mithral wood -- Darkleaf, from Eberron, and to a lesser extent, Bluewood... or even Ironwooded Darkwood (if DM rules that functions like Mithral, which is plausible).
Wildwood: A wood that heals itself. Races of the Wild. Can probably be folded into Livewood, or vice versa. Can be made into armor.
Hardwood: A generic hardwood for arrows, more durable than normal wood. Dragon Magazine 330. Can probably be folded into Darkwood, or Bronzewood or Coldwood, perhaps.
Livewood: A wood that heals itself. Eberron Campaign setting. Can probably be folded into Wildwood, or vice versa. Can't be made into armor or non wooden weapons.
Soarwood: Wood that starts out just a bit heaver than Darkwood, but, when alchemically treated, is buoyant in air. The basis for Eberron's airships. Airships might be beyond the scope of this game. Eberron Campaign Setting.
Densewood: An extra heavy wood. Can't be made into anything special. Eberron Campaign Setting.
Coldwood: Just as good as Iron, one of the few woods that can explicitly be made into ammunition, armors, weapons, etc. Can possibly be folded into Bronzewood. Dragon Magazine 357.
Fey Cherry Wood: A wood that is GREAT for making magic items. 10% reduction in the price of making a magic item from this wood and its leaves. No mention on if it can be made into weapons and armor, or how it responds to alchemical treatment (blueing?) or ironwooding. Dragon Magazine 357.
Ironwood: Not actually a wood in D&D. This is a spell that, when combined with an appropriate craft check or a shape wood spell, automatically makes the wood as hard as iron, AND has a clause that lets +1 weapons and +1 armors be made... with no expenditure of XP or even GP beyond the raw materials. Yet another reason Druids are overpowered... Also, the spell implies that this only happens with normal woods, like oak and such; no mention is made of any of the 'lighter than normal wood' options, ie, what would happen if you Ironwood a Darkwood breastplate? What happens if you Ironwood an alchemically treated Darkwood Breastplate (ie, a Darkleaf Breastplate)?. Would the former act like a Mithral Breastplate except for the hardness? Would the latter act like a Mithral breastplate, but with better hardness? Would that perhaps get the hardness all the way to Adamantine's hardness? Would it then provide Damage Reduction like Adamantine? Would a weapon of it bypass hardness in objects like Adamantine? Unknown, and possibly requiring DM intervention. PHB.
Oak: Only mentioned because non-magical oak is the only wood that the Shillelagh spell will work on, should the DM give armies access to this. PHB. This is an example of just plain old wood in the PHB.
By the way, that's a list of woods. Not plants or things you can get from the plant kingdom, but woods and woods alone...
OOC - The Fourth Wall
