Transition metals
The metals of the side groups: chromium, manganese, iron, copper, silver, gold and others, the lanthanides and actinides.
Material on this topic
Iron
Iron is the most abundant element on Earth if the whole planet is counted: the core is mostly iron and nickel.
Copper
Copper was the first metal people smelted from ore, and it named an age: the Bronze Age is the age of copper alloyed with tin.
Silver
Silver holds records: the highest electrical conductivity and the highest thermal conductivity of any metal, and the best reflectance in visible light.