Since you said any language, you have Free Pascal and its gui editor Lazarus.
För wxWidgets and C++ you have wxFormBuilder.
The Glade editor for gtk3 programs (C, C++, or whatever language one might use). (edit: just a gui editor that is used separately from whatever IDE or editor you write your code in)
You are missing the best one.
If you want to make great GUIs there really is no substitute for Qt with Qt Creator.
Nice GUI editor as you are used to in VS, C++ with the best documentation I've seen in anything open source.
Qt was the GUI toolkit that got me hooked on C++ back in the day. (https://www.qt.io/download)
Be aware there is a commercial and an open source version but you can relatively easily get the open source one from the online installer.
It was already mentioned by @RHOPKINS13 so I didn't bother.
As for Qt itself, I wasn't thrilled with their path regarding licensing back in the day, like only allowing GPL (not LGPL) on Unix like systems and attempting their own special licenses, and only offering a paid commercial license for Windows development. These days I can't say I find the $300+/month subscription option for commercial usage very appealing either. They can of course do whatever they want, just as I look at what is at my disposal and what's out there and choose according to my needs and preferences (which may be very different from other individuals). Essentially, their decisions early on soured my opinion of Qt (regardless of any technical merits), and since those days I have always had other options that have worked well enough for me. It may also have played a role in my relative lack of interest in KDE,
I'm just expressing my feelings, and it is not a statement whether anyone else should make any specific choices. :)