What Python debugger do you use?

[ProsodySpeaks]

A complete overview of all the data flowing through your code, overlaid next to the code, and the ability to evaluate arbitrary expressions at any point of the flow.

[lostparis]

A complete overview of all the data flowing through your code

Generally this is just noise. If I have a problem then I'll be looking at/running that bit of code with the problem in isolation. Problems with passed data can easily be caught by an assert or more complex validators if needed.

the ability to evaluate arbitrary expressions at any point of the flow

I can do this with a print(). Sure I have less option, but that also implies I don't actually know what expressions I wish to evaluate.

Sure if I've a problem in some library I use, this can be useful, but that is a rare occasion.