This is a theme that I’m not sure I’m qualified to talk about since all my interviews are done through Skype. That said, I’m still expecting people to not show up in their pajamas. It’s always a pleasant surprise when I see a candidate that evidently put in effort to show up for the interview even if it’s through a webcam (shirt and tie, combed hair), it says a lot about their level of motivation and commitment, though it’s not strictly necessary to show up like this.
Basically, long sleeved tops, a pullover, a shirt, a blouse, a t-shirt, any of these are good choices for an interview as long as they don’t have any weird patterns and stamps. (See how I’m only concerned about upper body clothing? I don’t usually see more than that during online interviews! I don’t really care if you wear pajama bottoms but do not let me know about it…). In any case, if you are feeling indecisive about what to wear, basic clothing can and should be the default choice as it is proper for any occasion.
If an employer / recruiter invites you to an onsite interview, then I only have two simple words of advice for you: business casual.