I haven’t actually played any of them though so I cannot vouch for the quality. D&D Adventures: has links to several free adventures.However if you search the archives for “FREE Original Adventure” you can still find them. These were listed on a single page but they’ve since taken it down. WOTC Archives: years ago WOTC released a slew of short free modules for Third edition.Wildgen: is an online random Hex-Map generator.DrawHexGrid: is a simple intuitive program that allows you to create a hex grid in various styles which can then be imported into your graphics program of choice.Inkscape Hexgrid: is an extension for Inskscape (an open source vector graphics program similar to Illustrator) that allows you to create a hexgrid in Inkscape.hexGIMP: is a script for GIMP (an open source raster graphics program similar to Photoshop) which comes with custom brushes and allows you to create and edit hex maps using GIMP.It is a Java-based program in which you “stamp” symbols onto hexes.
Hexographer: is far and away the most popular software for creating hex maps.
Feel free to let me know of any resources on the topic you find helpful as well. I’ll likely be adding to it as I discover more helpful information. In the meantime, here are a list of resources that I found helpful when thinking about how to design my own hexcrawl. I am midway through keying my Thild Island Map for my upcoming campaign and will be posting more on this in the near future.