Searching for someone not in a relationship
The 'Include/Exclude' search is very handy for situations like this:


create a group of all contacts of interest
create a group of those who DO meet some criteria
use include/exclude to include group 1 and exclude group 2 to
produce those who DON'T meet the criteria


So in your case:


create a group of all people 
create a group who do have a relationship (Advanced Search, open Relationships section, select relationship types of interest, search, save group)
go to Search &gt; Custom Searches &gt; Include/Exclude search  include your 'all' group, exclude the 'has relationship' group (select either AND/OR - doesn't matter since you are not using tags but it is still required)  Save as a group if you want.


If you want to use this often, create all 3 groups as smart groups.