Figma (front-end written in C++ and cross-compiled to JS)
LibreOffice (with Java)
Evernote (originally in C#, converted to C++)
Visual Studio (with C#)
Photoshop, Illustrator, InDesign, etc.
Most AAA games
Most pro audio and video production apps
Also see this list and some of the links here.
Most of Netflix
A large fraction of Amazon services
I'm not even going to make a list because basically every major microprocessor, NIC, switch, etc. is made in either VHDL or Verilog. For existing projects, you might say that this is because you have a large team that's familiar with some boring language, but I've worked on greenfield hardware/software co-design for deep learning and networking virtualization, both with teams that are hired from scratch for the project, and we still used Verilog, despite one of the teams having one of the larger collections of bluespec proficient hardware engineers anywhere outside of Arvind's group at MIT.
Please suggest other software that you think belongs on this list; it doesn't have to be software that I personally use. Also, does anyone know what EC2, S3, and Redshift are written in? I suspect C++, but I couldn't find a solid citation for that. This post was last updated 2021-08.
One thing I find interesting is that, in personal conversations with people, the vast majority of experienced developers I know think that most mainstream langauges are basically fine, modulo performance constraints, and this is even more true among people who've built systems that are really impressive to me. Online discussion of what someone might want to learn is very different, with learning interesting/fancy languages being generally high up on people's lists. When I talk to new programmers, they're often pretty influenced by this (e.g., at Recurse Center, before ML became trendy, learning fancy languages was the most popular way people tried to become better as a programmer, and I'd say that's now #2 behind ML). While I think learning a fancy language does work for some people, I'd say that's overrated in that there are many other techniques that seem to click with at least the same proportion of people who try it that are much less popular.
A question I have is, why is online discussion about this topic so one-sided while the discussions I've had in real life are so oppositely one-sided. Of course, neither people who are loud on the internet nor people I personally know are representative samples of programmers, but I still find it interesting.
Thanks to Leah Hanson, James Porter, Waldemar Q, Nat Welch, Arjun Sreedharan, Rafa Escalante, @matt_dz, Bartlomiej Filipek, Josiah Irwin, @jayachdee, Larry Ogrondek, Miodrag Milic, Presto, Matt Godbolt, Leah Hanson, Noah Haasis, Lifan Zeng, and Josiah Irwin for comments/corrections/discussion.