I linked a bank account and wasn't supposed to link it. I unlinked the account but all of the transactions are still showing. How do I remove all of the transactions?

It's my priority for you to remove the bank transactions in your account, altaylor.

Once you disconnect your bank account, QuickBooks Online (QBO) will stop downloading new transactions. Then, the downloaded data from the "For review" and "Excluded" sections will be deleted.

If the transactions are already posted in the Chart of Accounts, just manually open the transaction and delete them. We need to take its balance down to zero and get rid of the transactions linked to it.

Here's how:

1. Go to Accounting on the left menu.
2. Choose Chart of account.
3. Look for your bank account and tick the View register link. 
4. Find the transaction you'll want to remove and click it.
5. Press the Delete button and tap Yes to confirm.
6. If you want to void it, just click the Edit button. 
7. Tap More and choose Void.
8. Then, click Yes to confirm.
9. Press Save and close. Then, do the same steps for the next transactions you'll want to remove. 

In case you need to remove or delete an account, just check out this article for the steps and details: Delete an account on your chart of accounts in QuickBooks Online.

To give you more insights about managing your balance sheet, income, and expense accounts., refer to this link: https://quickbooks.intuit.com/learn-support/en-us/advanced-accounting/chart-of-accounts/08?product=Q.... 

That'll do it. I'm just one reply away if you need a hand with reconciling your accounts or any QBO related. Just leave a comment below and I'll be here to help. You have a good one.