All told, there are 58 people on the two ballots combined; 30 Republicans and 28 Democrats. The reason for such a crowded ballot? New Hampshire has a low bar when it comes to qualifying for the ballot. You need to sign some paperwork and pay $1,000. That's it.
Stunningly, this isn't the most candidates to appear on a New Hampshire presidential ballot. In 1992, there were a total of 61 candidates.