what are the different types of ocd

Checking - the need to check is the compulsion, the obsessive fear might be to prevent damage, fire, leaks or harm. Common checking includes:

Memory (checking ones memory to 'make sure' an intrusive thought is just a thought and didn't really happen).
Gas or electric stove knobs (fear of causing explosion and therefore the house to burn down).
Water taps  (fear of flooding property and damaging irreplaceable treasured items).
Door locks  (fear of allowing a burglar to break in and steal or cause harm).
House alarm   (fear of allowing a burglar to break in and steal or cause harm).
Windows  (fear of allowing a burglar to break in and steal or cause harm).
Appliances  (fear of causing the house to burn down).
House lights (fear of causing the house to burn down).
Car doors  (fear of car being stolen).
Re-reading postal letters and greetings cards before sealing / mailing  (fear of writing something inappropriate or offensive).
Candles (fear of causing the house to burn down).
Route after driving (fear of causing an accident).
Wallet or purse (fear of losing important bank cards or documents).
Illnesses and symptoms online (fear of developing an illness, constant checking of symptoms).
People – Calling and Texting (fear of harm happening to a loved one).
Reassurance  (fear of saying or doing something to offend or upset a loved one).
Re-reading words or lines in a book over and over again (fear of not quite taking in the information or missing something important from the text).
Schizophrenia Symptoms – (fear that OCD is a precursor to  Schizophrenia which will cause them to lose control).

Contamination – the need to clean and wash is the compulsion, the obsessive fear is that something is contaminated and/or may cause illness, and ultimately death, to a loved one or oneself.

Mental Contamination In addition to the more familiar type of contamination, that is commonly perceived to be the stereo-typical image of OCD, involving someone that washes their hands repeatedly after coming into contact with potentially dirty objects or environments, there is also a less obvious form called ‘mental contamination’.

The feelings of mental contamination share some qualities with contact contamination but have some distinctive features. Feelings of mental contamination can be evoked by times when a person perhaps felt badly treated, physically or mentally, through critical or verbally abusive remarks. It is almost as if they are made to feel like dirt, which creates a feeling of internal uncleanliness — even in the absence of any physical contact with a dangerous/dirty object. A distinctive feature of mental contamination is that the source is almost always human, unlike the contact contamination that is caused by physical contact with inanimate objects.