Accountable included Open Banking bank account aggregation service to their invoicing and accounting platform for freelancers. The Open Banking data allows their customers to track all payment transactions from the app without the need to access their banks. They use the data to reconcile invoices and expenses to help with tax returns.
PS: If you've ever paid/sent an invoice, you know how disjointed the experience often feels. This niche seems like one of those that are going to be hugely disrupted by Open Banking, especially when paired with Request to Pay payment tech. Watch this space.