I'll add my answer here in case it helps you and you can mark it as the solution. There's a couple of things that we needed to consider when creating a list of eligible accounts for the user to choose from:

1. We wanted to ensure that the accounts linked to the User's profile had view-permission. We utilize Member to Member transfers and when those accounts are linked to the User's profile, the permissions are set to deposit only (no withdrawal permissions or view permissions).
2. I wanted to ensure that the accounts were internal only - no external accounts.

To get the list of accounts, I used self.account_list.accounts

https://docs.q2developer.com/api_references/q2_sdk/hq/models/AccountList.html

This is my function to get a list of accounts that satisfied the two priorities above. However, you could probably use a set() instead of building a dict like I did to get unique values.

    def _get_unique_accounts(self) -> List[str]:
        """
        Returns a unique list of accounts for the Online Banking user with external accounts filtered out.
        """
        return [
            account.cif_internal_unmasked.zfill(10)
            for account in {
                account.cif_internal_unmasked: account for account in self.account_list.accounts if not account.is_external_acct and account.can_view
            }.values()
        ]

Hopefully this gets you going in the right direction.