Desmos: This is certainly my favorite teaching software because of how easy it is to use on any platform, including a free app that is better than any TI. This is the graphing calculator link, which is great for teaching demonstrations and for students to use as a tool on assignments. However, the real strength in Desmos is its Activity Builder, which is designed to compliment the skills of the teacher, rather than replace them. It is a nice way to build interactive activities for students with features that make whole class discussion a real possibility.
Geogebra: Although learning the syntax of Geogebra is more difficult than Desmos, it is quite accessible and there are plenty of group chats available that provide answers to any questions you may have. This is the software I used to produce all of my 3D graphics, a feature Desmos does not yet have. In each post using Geogebra, I have uploaded my file in case you want to use/edit anything I have done.
Pages: This is the word processor for mac, which I love because it has a built-in equation tool that utilizes the LaTex language without needing to code everything in LaTex. Many of the equations you found in activities were typed using the equations tool and then uploaded by screenshot. I also like Pages because of how easy it is to turn any document into a pdf.
WordPress: As you can see at the bottom of this website, it is powered by WordPress. Although I prefer Weebly (see below) for free website creation, the upgrade cost on WordPress offers a lot more storage for less. It has been dependable so far, though some features take a little while to learn, especially the menus feature. I think of WordPress as my professional platform and Weebly as my everything else platform.
Weebly: Another website creator that allows for additional customization compared to WordPress through drag and drop features. I have utilized this for class websites because of its ease of use and greater freedom than WordPress. I think of WordPress as my professional platform and Weebly as my everything else platform.
Google Earth: This can be downloaded as an application on your desktop or can be accessed via the web, but only if you are using Google Chrome as your browser. The app version allows for significant customization and includes historical imagery, making it useful for understanding how landscapes change over time.