Here is a list of Iowa candidates for federal and state office. The Libertarian Party and the New Independent Party of Iowa have candidates on the ballot for most of the statewide offices, and the Libertarian Party also has six legislative candidates. The Green Party has one legislative candidate.
The New Independent Party of Iowa is a new party, with a platform somewhat similar to the Reform Party’s platform. Here is the New Independent Party of Iowa’s web page. Thanks to Nathan Hetzel for the links.
Iowa has no ballot-qualified parties, other than the Democratic and Republican Parties. A group only attains qualified status after it has polled 2% for President or Governor. The Green Party had qualified party status 2000-2002, and the Reform Party had it 1996-1998. Otherwise Iowa hasn’t had any ballot-qualified parties, other than the Democrats and Republicans, during the last 40 years.
UPDATE: see this commentary by John Deeth, on the New Independent Party of Iowa.