Base for your tabletop, could be produced in steel or wood (oak).
Bottom side could be completed with adjustable feet (in most cases they are not needed and no need to pay extra money for it) – legs with anti-slip tape are stable and level your table on an uneven floor.
You doubt which legs to choose – wooden or metal? Wooden are more eco-friendly, while they are able to withstand almost the same load as metal. They can also have the same appearance as steel ones – they can also be painted black.