"Hand Loaded" rounds out of Firing Squad would work for Iron, Gold, Silver. If you want to apply an up charge for precious metals, go for it. Many melee weapons could include Gold or Silver, in addition to Iron. I'd suggest the Custom Style modification out of Firing Squad, p. 58.
Real World incendiary rounds are a thing, just haven't been stated out yet in 6E. But, again, see Firing Squad for assorted Exotic weapons and Grenades that cover Elemental damage (Fire, Cold, Electric) if you want a RAW option. Otherwise, whatever homebrew option you've got is fine.
Wooden bullets, not a thing at all, they'd likely burst into flame in the barrel. But see "Glitter Grenades" out of Firing squad for splinter grenades or just use a club of some sort. Wooden Arrows and bolts also a thing.
Toxic, yup, Pepper Punch is cheap and is in the CRB. Variety of delivery options including Bullets, see Injection Darts entry under "Ammo" on p. 262. Or Gas Grenade on 263 CRB.
Stick and Shock for Electric, also a variety of melee options.
A typical Street Samurai with multiple combat skills can easily cover all these. Pack an Ares Predator (or whatever) with Stick and Shock, Pepper Punch Injection Darts, Hand Loaded Iron, Gold, Silver, rounds. Fire, Cold, Corrosive and Wood require Melee, Archery, or Grenades for a RAW solution. A home game can easily come up with other solutions.
Injection Arrows and Bolts out of the CRB can also cover Toxins (and possibly Corrosives if the GM lets you buy Acid), and gold, silver, iron, wood tips are also options. An Archer easily covers all but Fire, Corrosive and Cold, and theoretically Fire Arrows should be a thing. I Recommend the smart quiver out of Firing Squad to help with Arrow selection.