@bunhyan
As @Korina said, you can find Isotherms and Geopotential heights in More layers…
Isobars are never shown at high level, afaik. Geopotential heights are the altitude of a pressure level e.g. 500hPa. They are usually expressed in dam (decameters) but in Windy they are shown in meters.
Here is an example of Isotherms at 850hPa.
CB09EE72-090D-4EC9-93D9-88158545C34F.jpeg