A nearly ubiquitous free Microsoft-provided download to provide for easy zooming, live zooming, drawing on your screen, and more. It is something that makes a big difference when communicating to an audience. Won't make you a better presenter, but will make your content clearer and easier to communicate. Be sure to practice with it before you go live. :)
An open source alternative to other screen recording, screen capturing, even making quick .gifs and uploading them to social media, image sharing applications and more.
An open source alternative to BeyondCompare that has many of the same features, including file and folder structure comparison. I commonly use this to compare large result sets to make sure that my query tuning hasn't drifted the outputs, or to compare two queries to find differences. It's a quick and easy application when this type of text or file comparison is needed. I've been using it for years for these purposes.
Visual Studio Code
A Microsoft-provided open source rich text editor that has a lot of the features you see in expect in Visual Studio, but in a lightweight, quick-loading text editor that compares favorable to other paid alternatives. It's replaced other alternatives for me for lightweight code editing.
SentryOne (formerly SQLSentry) released a user-friendly, feature rich, useful alternative to the SSMS execution plan viewing options that is particularly useful when analyzing massive, complex query execution plans and breaking down costs. The guidance provided is obviously solid technically and can deliver valuable insights. It even has integration with SSMS. A premium paid version has collector service and database.
Also: You should of course also check out new features that have been added to SSMS recently, including Live Query Stats and the Query Store. SSMS itself is a little obvious for this list.
Remote Desktop Connection Manager (RDCMan)
Not to be confused with Remote Desktop Manager or any similarly-named browser extensions, RDCMan is a free Microsoft-provided tool that makes it easy to organize remote desktop connections, securely store credentials for groups of RDC's, for example in a domain. This is a dream tool for folks who have many RDC's with many credentials in many different domains.
Sidebar: Do you get an annoying popup when you open your RDCMan application, "There were problems decrypting some credentials"? That's the built-in encryption that keeps your stored credentials secure. You'll get that (and lose the stored passwords) when you migrate from one machine to another. You'll have to open the .rdg file and remove the password hashes. There are instructions in the RDCMan help to migrate a personal certificate along with the .rdg file for proper migration, it's the only way to have remembered passwords transfer to another device. (I've been meaning to blog about this over time, but didn't feel it was worthy of its own post.)
Okay, maybe this isn't free, but it comes with your Office365 account or office license for Word and Excel, so unless you're in a no-Microsoft environment, you have access to OneNote for free.(Teachers and students globally can also get all of Office365 for free.) Had I known about OneNote back in college I'd have been using it then. OneNote is a fantastic information-gathering tool. It can do quite a lot more than a simple note-taking platform. We share password-protected OneNote notebooks on SharePoint for secure team-based collaboration and note taking. And the search function can find word matches in your notes and handwriting, and even in your screenshots, photos, and audio recordings, something you can't do with stacks of legal-size notepad paper. I've presented using OneNote as a whiteboard before as well, and it performs admirably with your drawing pad or tablet touchscreen.
Caveat: By default, the Ctrl+1 zoom feature of ZoomIT (above) and the Ctrl+1 checkbox feature of OneNote make for exciting note taking. The good news ZoomIT is easy to close and re-open.Slack
The ubiquitous rich persistent chat app has set a very high bar for other collaboration tools, including the me-too Microsoft Teams. It's free but you have to pay for history and some other features. It's got a million different integrations, is very popular in the tech world for internal corporate team communication, but also in the social activism communities and technical user community, especially in the SQL Server community. The richness of the medium allows for better responses when you're crowd-sourcing SQL help than the twitter hashtag #SQLHelp, which is still popular. Speaking of which...
There is no larger or more popular platform for short-format communication this day and age, used by everyone from teenagers, heads of state, even teenaged heads of state. Hashtags are topics, so posting a question accompanied by #SQLHelp will allow others anywhere in the world to see your post if they follow that topic. Twitter has most impact during live events, especially physical events like conferences, but also sporting events and breaking news. The next time you're at a SQLSaturday event, check out the hashtag for the event, for example, #SQLSatBR at SQLSaturday Baton Rouge. If you're at PASS Summit in the fall, try #SQLSummit. Also, reading about their architecture for outrageous growth scale is interesting.
Quick unsolicited advice: If you're on Twitter, you should try to keep your professional and personal lives separate. You know you shouldn't launch political tirades on LinkedIn or in front of your coworkers or at the Thanksgiving dinner table. You should use your professional platforms to interact with technical peers and colleagues and coworkers, and to represent your employer (and future employers). Use your personal, potentially anonymized account(s) to hurl insults at sports rivals and to argue over whether the dress was blue or gold. As a consultant who tried to keep public work and politics separated, the benefits to this strategy are clear. If you're a government employee, this is probably required of you too.Microsoft Assessment and Planning Toolkit
Does a yeoman's job of collecting IT infrastructure inventory in your environment, including SQL Servers, via a variety of connection methods and all without an agent. Generates a bunch of reports that CIO's and managers will eat up. Has delivered good value with minimal investment in time or expertise.
Yep, there is a capable free version for organizations, assuming those organizations have an Azure tenant/Office 365. It is also free for individuals who are not in those organizations.
Aardvark is a really neat social tool that allows you to source answers come from other users who have signed up for knowledge in general categories. It's really going to change the world.
Just kidding of course, but it was cool in a make-the-world-small kind of way for a while there before Google bought then killed it in 2011.