Data

Natural Earth: A website with public domain map data in both vector (points/lines/polygons) and raster (pixels) formats. There is a wide range of cultural and physical datasets available at scales of 1:10 million, 1:50 million, and 1:110 million. Shapefile (.shp) and TIFF (.tif) downloads can be opened directly in QGIS or ArcMap.

Earth Engine Data Catalog: a vast repository of geographic data, much of it collected by satellite, that can be manipulated in Google Earth Engine's code editor, which runs on Javascript. Look here for data on temperature, elevation, precipitation, climate, fire, forest cover, nighttime lights, and much more.