A smart list is a saved filter on the Contacts page. You set filters such as tag, custom field value, date added, last activity or opportunity status, then save the view. It's dynamic: contacts appear and drop off as they start or stop matching the filters. A smart list doesn't copy contacts anywhere, it's just a reusable lens on the contact database.
In practice
Go to Contacts, add the filters you want, and save them as a new smart list (as of October 2026). It then shows as a tab you can open any time and can be shared with other users in the sub-account.
Smart lists are where most manual outreach starts. Pick the list, select all, and run a bulk action: send an SMS or email, add or remove a tag, add contacts to a workflow, or export. A common pattern is to filter by a tag that a workflow or form added, so the list stays current without anyone maintaining it.
The limit is the filters themselves. A smart list can filter on what's stored on the contact, but there's no built-in filter for something like "received last Tuesday's blast and never replied by text, call, email or chat." Questions like that need the answer written onto the contact first, usually as a tag.
Where it shows up in RGS Tools
Blast Follow-Up does exactly that pre-work. The no-reply checker checks each blast recipient's reply history, and the resend tagger adds a dated tag to everyone who never answered. Filter a smart list by that tag and your resend audience is ready.