Single-sided (cheapest), double-sided (most common), multilayer (4-50 layers for complex products), HDI (smartphone class), Flex (bendable).
FR-4 material (glass-epoxy, most common). Copper thickness: 1oz (35um) standard. Board thickness: 1.6mm standard. Line/space: 0.2/0.2mm for standard, 0.1/0.1mm for precision.