It's common. Months after a death, small charges are still going out: a gym, a cloud storage plan, a streaming service, an app nobody knew about. Each needs its own call to stop.
Where to look
The last 12 months of bank and credit card statements (to catch yearly renewals)
App Store or Google Play subscriptions on their phone
PayPal automatic payments
Their email inbox: search for “receipt”, “renewal” and “subscription”
Good to know
Cancelling the card isn't always enough. Some card networks automatically pass new card details to merchants, so cancel subscriptions directly too.