Material                 (alloying formula) aka notations hardness, ductility corrosion resistance color already used wire diameters [mm] notes
Note: Not only wires obtained as welding wire (while they might been originally such as well) are shown here; these wire types are marked with a star (*)
 
Aluminium  
* Al  Aluminium fence wire very soft high, but see notes silver, grayish hue ~2.0 'dirty' wire, gives blackish rub-off
Al99.5Ti 3.0805, AL1450 very soft high silver, grayish hue 1.2, 1.6 polishable, but quick redulling - and gives ruboff
SG-AlMg3 ER-5154, 3.3536 inbetween Al and ALMg5 high silver, shiny 1.6 fairly ok, better than pure Al or AlSi anyway
SG-AlMg4,5Mn ER-5183, 3.3548 springy, half-hard to hard high silver, very shiny 0.8, 1.0, 1.2, 1.6 my currently favourite Al-wire, a bit higher hardness, and higher toughness than standard BA, even tends to break if bent over edges
SG-AlMg4,5MnZr ER-5087 springy, half-hard to hard high silver, very shiny 1.0, 1.2, 1.6 similar, if not a bit harder than my top favorite. Tumbles to the highest shine of all BA alloys.
SG-AlMg5 ER-5356, 3.3556 springy, half-hard high silver, shiny 1.0 another of my favorites, this alloy is the usual "standard BA"
SG-AlSi5 ER-4043, 3.2245 relatively soft compared to AlMg* alloys medium, darkens a bit with aging silver, shiny with a bit grayish hue 1.6 not very good for anodizing, and imho also too soft for maille.
             
Copper  
* Cu Electrical wire (salvaged) very soft principally high, but not corrosion resistant copper-typical, reddish, tarnishes quickly, on some people up to near-black ~1.4, ~1.7, ~3.6 nearly no springback
SG-CuAl8 "Aluminium Bronze" 2.0921, ERCuAl-A1, CastoMag 45751 hard, spring temper, but very ductile and tough as well - somewhat beasty high; sea-water resistant, but tarnishes as well golden, brass-like,  tarnishes slowly to light bronze-tone, sometimes slightly greenish when aged 0.8, 1.0, 1.2, 1.6 HIGH springback; alloy is very similar to 'nordic gold' as used in e.g. 10, 20, 50 Eurocent, or 2AUD coins; see http://www.predecimal.com/euroarticle.htm
CuSn1 S ERCu relatively soft for Bronze, very ductile, hard enough for maille high; tarnishes like pure Copper does Copper-like; tarnishes slightly more brownish than pure Copper 1.0, 1.2, 1.6 As springback and hardness are very similar to good Bright Alu, same nominal wire/mandrel data lead to similar resulting rings. My personal favorite Bronze
CuSn6 / CuSn5P S ErCuSn half-hard and tough high; tarnishes to a deeper brown, compared to Copper Copper-like; tarnishes brownish 0.8, 1.2 Good universal Bronze
CuSi3   half-hard and tough tarnishes to a deep brown golden, but tarnishes to a deep brown hue 0.8, 1.0 Not my favorite, except extra-dark tarnishing rings are asked for
             
Iron/Steel  
SG-2 ER-70, 1.5125, G3Si1,  "common MIG wire" medium low copper-like 0.6, 0.8 Copper plated mild steel, plating rubs off quick, remaining wire rusts "as hell"
SG-X10CrNiMn19-9 ER-307(mod.), 1.4370, Thyssen Thermanit X not really hard, but very tough excellent iron, a bit darker than 1.4316 1.0, 1.2, 1.6, 2.4 My favourite Stainless wire, used also as WIG-rods (1.6, 2.4) - a bit softer temper as same diameter MIG-wire
spring temper and tough slightly matte 1.2, 1.6 newer MIG wire batches I recently got - need a thorough tumble to become shiny
SG-X5CrNi19-9 "18-8", ER-308L, 1.4316, "V2A" tough, smaller diameters springy half-hard excellent iron, shiny 0.6, 0.8, 1.0 good stuff, 1mm VERY springy
SG-X10CrNi22-12 ER-309(mod.), 1.4829, Thyssen Thermanit D relatively soft, compared to other Stainless excellent extremely shiny 1.2 soft' is meant as 'not springy'
SG-X2CrNiMo19-12 ER-316L, 1.4430, "V4A" springy, like ER-308 excellent iron, very shiny 1.0, 1.2 similar to "surgical steel"
SG-X10CrW9-2 T92, P92, Thyssen Thermanit MTS616 springy, a bit harder than 1.4316/1.4370 good, but not 100% rust free silver, very shiny  0.8 nearly nickel-free (may be anti-allergen); got it by chance, but like it
             
Titanium    
* Ti6Al4V Ti Grade 5 springy and tough excellent gray, usually slightly matte - in anodized state a wide palette of achievable 'pastel' colors, as the material stays matte 0.65, 0.9, 1.2 Titanium is hypo-allergic, and can be anodized for dye-less coloring
             
Else    
* Niobium formerly known as Columbium tough, but not really hard excellent grayish, but shiny; very similar to stainless steel - in anodized state a wide palette of vibrant colors achievable 0.5, 0.6, 0.8, 1.0, 1.2 Niobium is hypo-allergic, and can be anodized for dye-less coloring, colors very vibrant compared to Ti