Fear of:

  Phobia

Machines  Mechanophobia.
Mad, becoming  Lyssophobia.
Many things  Polyphobia.
Marriage  Gamophobia.
Materialism  Hylephobia.
Matter, decaying  Seplophobia.
Meat  Carnophobia.
Medicine, taking; or drugs  Pharmacophobia.
Medicines, mercurial  Hydrargyophobia.
Memories  Mnemophobia.
Men, bad or burglars or being harmed by wicked persons  Scelerophobia.
Men  Androphobia or Arrhenphobia or
 Hominophobia.
Menstruation  Menophobia.
Mercurial medicines  Hydrargyophobia.
Metal  Metallophobia.
Meteors  Meteorophobia.
Mice  Musophobia, Murophobia or Suriphobia.
Microbes  Bacillophobia or Microbiophobia.
Mind  Psychophobia.
Mirrors or seeing oneself in a mirror  Eisoptrophobia.
Mirrors  Catoptrophobia.
Missles  Ballistophobia.
Mobs or crowds  Demophobia, Enochlophobia or Ochlophobia.
Moisture, dampness or liquids  Hygrophobia.
Money  Chrometophobia or Chrematophobia.
Moon  Selenophobia.
Mother in law Pentheraphobia
Moths  Mottephobia.
Motion or movement  Kinetophobia or Kinesophobia.
Moving or making changes  Tropophobia.
Moving automobile or vehicle, being in  Ochophobia.
Muscular incoordination (Ataxia)  Ataxiophobia.
Mushrooms  Mycophobia.
Music  Melophobia.
Myths or stories or false statements  Mythophobia.
Names or hearing a certain name  Onomatophobia.
Names  Nomatophobia.
Narrow things or places  Stenophobia.
Narrowness  Anginophobia.
Needles  Aichmophobia or Belonephobia.
New, anything or novel  Kainophobia, Kainolophobia, Cenophobia,
 Centophobia, or Neophobia.
Newness  Cainophobia, Cenophobia, Centophobia, 
or Cainotophobia.
News: hearing good news  Euphobia.
Night or dark  Nyctophobia.
Night  Noctiphobia.
Noise  Acousticophobia.
Noises, loud  Ligyrophobia.
Noises or voices, speaking aloud, or telephones  Phonophobia.
Northern lights  Auroraphobia.
Nosebleeds  Epistaxiophobia.
Novelty or anything new  Kainophobia or Kainolophobia.
Novelty  Cainophobia or Cainotophobia.
Nuclear weapons  Nucleomituphobia.
Nudity  Gymnophobia or Nudophobia.
Number 8  Octophobia.
Number 13  Triskadekaphobia.
Numbers  Arithmophobia or Numerophobia.
Objects, small  Tapinophobia.
Ocean or sea  Thalassophobia.
Odor, personal  Bromidrosiphobia, Bromidrophobia,
 Osmophobia or Osphresiophobia.
Odor, that one has a vile odor  Autodysomophobia.
Odors or smells  Olfactophobia.
Official doctrine, challeges to or radical deviation from  Heresyphobia or Hereiophobia.
Old people  Gerontophobia.
Old, growing  Gerascophobia or Gerontophobia.
Open spaces  Agoraphobia.
Open high places  Aeroacrophobia.
Operation, surgical  Tomophobia.
Opinions  Allodoxaphobia.
Others, dependence on  Soteriophobia.
Otters  Lutraphobia.
Outer space  Spacephobia.