Suppression lists can be used to omit select recipients from a campaign without permanently altering the sending list. Suppression lists do not count towards your total list size and will always show an active count of 0.
Suppression lists can be used to omit individual addresses, domains, or local addresses all in the same list.
Here's a list of possible examples that can be used in a suppression list:
*@yahoo.com - will omit all yahoo.com addresses
*@yahoo* - will omit all yahoo domains (yahoo.co.uk, yahoo.com, yahoo.co.in, etc)
noreply@* - will omit all noreply addresses