I use a lot of mindmaps to keep my thoughts organized. For that: XMind.
Since my IoT application uses serial communication: Visual Studio community edition (C#)
Since I like Python for simple scripts, I have Visual Studio configured for Python as well.
I sometimes prefer to use Python’s Idle editor. (Got to be a habit when my sysadmin didn’t allow me to change things in a previous job)
For screenshots, I use Greenshot.
For editing screenshots (i.e. “Look at the problem HERE!”), Paint.net
For analyzing logs, Notepad++
For API tests, Postman
Free software that I use regularly as tester as like as for other tasks:
• Notepad++: for all files you may edit, esp. with XML-Tools (pretty-print!) by the way Notepad+ can replace many of the tools the author of the fifteen-free-tools blog post suggests!
• AutoIt: esp. for automating WIN-UI tasks like stepwise performance tests (automated testcase by compiling .exe)
• AutoHotkey: esp. for automated string manipulationg task in our bugtracking system
• Sikuli: for quick regression testing (as non-dev I could not find a easy solution to automate with other scripted tools due to many “black-box” components)
• GoldenDict: translating tool I use not primary for testing but for documentation and support tasks also with dictionaries created with babylon builder on my own to have immediately access to things like our products terms (translations) database, internal IDs to descriptive terms ect.
• TNTscreencapture: does what is says
• Bandicam: for creating short screen videos, but as freeware with watermark
• DiffPDFportable: already saved a lot of time (but to admint rarely used)
• Sysinternals Suite: indispensable with tools like perfmon, PsExec, zoomit, autoruns, Bginfo
• www.di.fm: can help a lot to make your brain stay focused on track (e.g. with Chillout dreams; Nightcore)