If it is just about account retrieval, then you can use below API to fetch account. Also, you can use a lot of filters in this API to narrow down your search.
Are you looking to act only on new accounts aggregated? In that case you may use “Source Account Created” trigger and the workflow will trigger for each new account created in ISC.
In case you need to act on updated accounts then you can use “Source Account Updated” trigger.
If you want to capture both cases, then you would need 3 workflows
A common workflow that accepts account ID and runs the action you need to on the account created or modified
A workflow that gets triggered when a new account is created and calls the workflow #1 passing the account ID
A workflow that gets triggered when an account is updated and calls the workflow #1 passing the account ID