I am trying to figure out which banks work with Quickbooks so that I would be able to see the attachments (deposit check) when I reconcile...Does anyone know of any?

Hello there, kjones. 

Allow me to share some insights about the supported banks in QuickBooks Online. 

QuickBooks Online is built with the ability to connect with a variety of banks and financial institutions to import and categorize transactions. However, the data may vary between different banks and financial institutions. To determine which financial institution provides attachments when synched to the program, I recommend reaching out to the respective bank for the most up-to-date information.

On the other hand, if you want to know which bank supports importing bank statements to help you reconcile your account, you can access this article and check the list of the supported banks in QuickBooks Online.

Additionally, you can categorize your bank transactions to manage them before the reconciliation process. 

Also, I'll leave this article if you want to import attachments or delete them manually in QuickBooks: Add or delete attachments in QuickBooks Online.

Keep us posted if you have other concerns about the supported banks and other QuickBooks-related. We're ready to help you and address it to help you manage your account smoothly in QuickBooks. Have a nice day!