I’ve historically used PySide (the free-license version of Qt) but for simple stuff like you’re looking for, you might get some mileage out of the Toga GUI toolkit. It’s relatively new, but promising.
I’ve actually been pretty impressed with the whole suite of BeeWare stuff in my informal testing so far; it’s a nice little bundle of tools. (Specifically I’m interested most in their distribution approach; building Python apps for distribution is a giant fucking pain, but this group seems to have improved the experience significantly.)
I haven’t used it much myself, it could be too early in it’s development to be useful, just thought I’d mention it though!
It looks like tabs are supported, but they call them an OptionContainer.
It seems like one sacrifices a lot of customizability for simplicity of code with this toolkit, but that might be fine for some use-cases.