There are definitely many questions about the usage (or lack thereof) of か in casual speech. Although it is relatively common in anime, it sounds harsh, maybe rude in everyday casual speech.
Alright, understood. My question then is: when do we use it? I know of embedded questions, such as:
"do you know what they bought"
But I'm not interested in those. I know of 何か and 誰か as distinct words, but I'm not interested in those either. I think I've heard things like:
Where the か is in a quoted clause, and I am interested in those, as well as things like:
Which I understand can mean something like "as if I could do it".
Basically, besides embedded questions, when might we actually use か in casual speech?
Edit: although sundowner's answer is helpful, I'd also like to hear maybe a more informal description, with examples, of when casual questions use か, since sundowner's answer only says that questions can take か.