Site: https://regex101.com/
This is a website sandbox for learning [or testing] regex expressions. You are able to search the command repository for commands that may be of help for you, and then you are able to see your regex working in real-time, when run on provided test strings. This was invaluable when I was learning how to use RegEx, and I still go to this website when I am working on complex RegEx to validate how it will work.
Site: https://www.gitkraken.com/
Git Kraken is a heavily advertised Git GUI. It is a free application for open source projects and $50/year for an individual license. Prior to finding Git Kraken, I used Atlassian SourceTree, which is also on this list and is free. I found that GitKraken has an easier to use interface for almost all basic Git tasks. Atlassian has a better code diff tool and is able to perform more complex operations, which Git Kraken has some difficulty with.
Site: https://www.virtualbox.org/
This is the best free utility that I can found for spinning up virtual machines, without having a huge administrative overhead. Great for setting up linux machines to learn new technologies
Site: https://code.visualstudio.com/
Versatile and extensible code editor.
Site: https://www.sublimetext.com/
This is a program that I had saw used by programmers at conferences and it took awhile to get a hang of using the tool. Memorizing a few key shortcuts really made this tool my go to for anything with a textual element. You can paste code into the editor purely for formatting, you can perform mass edits to multiple lines at once; multi-cursor selection. This program is really a text editor on steroids.
Recently, I have been referred to VSCode, which I have been actively testing. VSCode is a free alternative with similar functionality. It also appears to be more frequently maintained than Sublime Text.
Through the use of this program, I came across numerous packages that helped with performing various tasks. Below are some of the packages that I use frequently. Their descriptions can be viewed at https://packagecontrol.io/
Site: https://jsfiddle.net/
This is a small sandbox for learning or testing different web technologies. You are able to have 3 panes for HTML, Javascript, and CSS; a fourth pane will then display the output, based on what you type in the other three panes. This website provides the ability to use numerous frameworks such as JQuery, Angular, React, etc.
Site: https://sourcetreeapp.com/
This is robust, free, Git GUI application. The interface can be intimidating at first, however, it provides all functionality that could be required for a GUI for the Git client.
Site: https://www.litmus.com/
This is a service that allows for mass testing of emails across multiple devices/operating systems at once. Great for testing responsive emails and if you receive user feedback from a user with a particular type of device. Unfortunately, this is not a cheap service, and is likely best left to businesses.
Site: https://www.emeditor.com/
emEditor is a tool that I purchased for a specific need, and SublimeText was not able to handle it. I needed the ability to open an extremely large CSV file and manipulate the CSV data in bulk. Specifically, the CSV had sporadic use of quoted cells, commas where their shouldn’t have been, etc. emEditor was able to open the file and, in attempting to parse the CSV, it was able to pinpoint lines that had a mismatch in the number of columns for the CSV. This allowed me to correct those records manually. Another feature that I used at the end of the project was the ability to mass-quote each individual cell, for consistency. Although not quite to the point of excel and its formula language, emEditor allowed for tabular display of CSV data, which allowed for quick sorting of data.
I still do not use this editor on a consistent basis, but it has unique functionality that I have not been able to find anywhere.
Site (Free): https://dbeaver.io/
Site (Paid-Enterprise Edition): https://dbeaver.com/
This is a connection manager for databases. You can share common settings amongst connections, color code connections, and standardize your keyboard shortcuts across different SQL languages. Free edition should work for most users; paid edition includes advanced export functionality and more connection options.