Although New Hampshire does not require independent candidates, or the nominees of unqualified parties, to submit petitions until August, such candidates must file a declaration of intent by June 10. Here is a link to the Secretary of State’s web page, showing the list of candidates who filed. Click on “List of candidates filing declarations of intent.”
For president, four candidates filed: Gary Johnson, Jill Stein, Darrell Castle, and Rocky De La Fuente. The first three are the nominees, or the likely nominees, of the Libertarian, Green, and Constitution Parties. De La Fuente is an independent candidate who is domiciled in San Diego, but who is now living in Florida. He ran in many Democratic presidential primaries this year.
For Governor, Libertarian Max Abramson filed, as well as three independents: William Fortune, Jiletta Jarvis, and Michael Gill.
For U.S. Senate, Libertarian Brian Chabot filed, as well as two independents, Aaron Day and John Riggieri. Thanks to Darryl Perry for the link.