If you’re looking for FREE audit work plans, AuditNet.org is probably your best bet.
You can get a free account that allows you to access a limited number of work plans, usually basic ones. A premium account gives you access to all content . See their Subscription Plans for more info, and note that they call work plans ‘audit templates’.
If you have an ACL support agreement, you may be able to access AuditNet for FREE!
Last time I looked, over 100 work plans were free, and a total of 2600 were available.