Kitchens in German rentals

It is very common to rent apartments completely empty and put in everything yourself (incl. kitchen, light fixtures and curtains). When looking at rental ads, this is the default (i.e. if nothing else is mentioned).
There are no rental kitchens - you'd have to buy one in this case (e.g. from Ikea or other kitchen furniture shops). It is not worth looking for a second-hand kitchen, because the cost of taking built-in stuff out of the previous flat and fitting it into the new one is half of what you'd pay for a new one. At the end of your lease, you might be able to sell the kitchen to the next tenant.
But there are also apartments for rent with fitted kitchens present. This is specified in the ad as "Einbauküche" or "EBK".
There are very few apartments with more furniture (or even fully furnished) and these are very expensive.

Cold rent ("Kaltmiete" or "KM") is the rent exclusive any utilities, Utility costs ("Nebenkosten" or "NK") are often broken down into Heating (which must be billed based on usage, according to energy savings regulations) and others (which can be a lump sum). These others include water, garbage, maintenance, insurance, tax, etc. Electricity is usually paid directly by you to the provider.

Thanks Beppie, that's very helpful!