Fats are an important part of your diet. The old school diets often say you should be eating low fat but that is so wrong.
You need a minimum of 20% of your calories to come from healthy fats. I would recommend at least 30%, and even up to 40% for some people.
And your fats need be divided about equally from unsaturated, polysaturated and saturated fats. Yes I said saturated fats - they ARE in fact good for you and you need them. They are found in solid form - so butter, meat, coconut oil to name a couple sources.
It's the evil TRANS FATS that you need to avoid. These are man made fats and are very unhealthy for you.
Here are some healthy fats;
Nuts (especially almonds and walnuts, preferably organic), extra virgin olive oil (not to be used for high heats), coconut oil, organic butter (non-organic butter is full of toxins), fish oil, GLA, organic free-range eggs (see earlier post about why eggs should be organic and free range), meats, fish, avocado, organic nut butters (non-organic nuts butters and full of pesticides). Of course there are more but if you are looking to add fats into your diet here is a good start.
Remember fats are much higher calorie so if you add fats into your diet make sure you know how much carbs and/or protein to take out to balance your calories. Or make changes and just watch what happens and adjust as needed if you don't want to count calories.