Get all design documents in CouchDB

New answer for an old question. From v2.2, you can query the _design_docs endpoint for a database: See the docs for deatils, but as a simple example:

GET /dbname/_design_docs

Parameters to the endpoint are consistent with other bulk APIs, like _all_docs.

This is the exact query Futon does internally:

GET /dbname/_all_docs?startkey="_design/"&endkey="_design0"&include_docs=true