Perhaps i'm not understanding your problem but the tab key, in it's normal working mode, is a repeating key. That means it keeps sending tabs until it's released. Unless something has reprogrammed the tab key it should already do what you say you need. Try using the tab key in a Notepad window and ...

I was attempting to create a script which spammed the Tab key when held, but couldn't make it to work. Can any of you please help me? And before you tell me to use the search bar and check other threads, I couldn't find one which spammed tab, or create one myself which worked. Thanks everyone!