I only have one job/W2 and my federal withholding is higher than reported on my W2. Where did the other withholding come from? It won't add up now

I have to input the quarterly withholding.  But i only have the 1 W2 with an annual withholding.  This withholding is lower than what TurboTax says is being withheld.  Where did the other withholding come from?  I have a TD Ameritrade and Robinhood account, but I don't think they have done any withholding