/r/MapPorn Guide to Making Maps
Quick, Simple Maps
mapchart.net for making quick simple maps that can be filled in with different colors.
Adobe Illustrator A powerful, but expensive program used to make vector graphics. Used by many professional cartographers.
Inkscape A free alternative to Adobe Illustrator.
ArcGIS A powerful suite of software programs used in the GIS industry to make maps. Expensive, but powerful.
QGIS A free and open source alternative to ArcGIS. Takes some time to learn and can be a bit clunky, but very useful in making good maps.
Powerglobe for Illustrator Free tool to make beautiful custom globes in Adobe Illustrator
Project Linework A collection of alternative shapefiles
Color Brewer 2.0-Color Advice for Cartography
Metro Map Creator Create London Underground style maps.
OpenStreetMaps An open source alternative to Google Maps and Apple Maps etc.
Adobe Illustrator for Cartographers from GeoMindz
/r/GIS Subreddit for Geographic Information Systems
/r/Worldbuilding a subreddit for building fantasy and fictional worlds
Cartographer's Guild A forum founded in 2006 for studying and discussing mapmaking and cartography. Includes monthly contests, tutorials and other events.
CartoTalk-A public Forum for Cartography and Design