For python, try Pycharm. There's also community edition, which may or may not be enough for you. Another step up is Intellij Idea, which supports everything that all the other language-specific products together.
For a nice Delphi alternative, try Lazarus (http://www.lazarus-ide.org/). Like Delphi 7, but with more features. Documentation could be better though.
For a decent dev tool under Linux - what about MonoDevelop? VSCode looks ok, but I haven't tried the Linux version, but apparently you can do C# development in it.
I'm not really up to speed with C# dev these days, last job I had which required C# was 2009, and since then I really haven't done much serious development in it (It's 95% Delphi professionally, and Python for my own stuff)
Edit: I wanted to re-iterate, I absolutely love Python Tools for Visual Studio. Those guys have created (what I have found to be) the highest quality python development tool I have experienced. The downside is it requires Visual Studio. If they can take what they have added to VS, and re-produce that in VSCode.... Wow, I would be very happy.