Where to get lists of leads?

[Anonymous]

I understand that you can get a list of leads under Programs and Static Lists (/rest/v1/list/{listId}/leads.json), are there other parent objects under which I can query for groups of leads in the same way? E.g. Smart Lists, Campaigns

[SanfordWhiteman]

Smart Lists are not yet generally available via API.

In Marketo, Campaign "membership" is not managed in the way you seem to think. It does exist in a sense, but there would be little to no utility to such a query. Programs, Lists, and Smart Lists are the collection types you want.