>>9296182>>9296314Most folks use Evergreen Poly Sheeths, but you can get bigger sheeths for less from architecture suppliers. One of them will last a real long time, lemme tell ya, but you should generally get them in all available thicknesses unless you´re really into stacking and planning stacks.
Their I, T and H bars and inch-based pipes and rods will usually do, but if you´re looking for actual milimeter-sized wares, you´ll have to refer to architectur suppliers again. I also think they have a cut-off point in terms of diameter, so you will likely be forced to use acrylic rods and pipes at some point. Paper hardened with superglue and aluminium bits from soft drink cans are useful in many projects as well.
Epoxy Putties are usually used for sculpting, with Miliput taking better edges and Greenstuff-equivalents doing better at actual organic objects. That Anime figurines book should have more on that.