Many more things than I previously thought can be considered addiction, so I was wondering whether an addiction is always bad
As I pointed out in Technical term for "hidden addictions", the term addiction is defined as not having control over doing, taking or using something to the point where it could be harmful to you. Often it can start with a habit but then it becomes an addiction because there is a compulsion to continue the habit.
You can continue with your daily life without carrying out a task which is habit, but if you are addicted to doing it you have a feeling of necessity to do it otherwise you cannot function.
Addiction is most commonly associated with gambling, drugs, alcohol and nicotine, but it's possible to be addicted to just about anything
So to answer your question, there can be good habits but there are no good types of addiction as they affect your life to the point where you "cannot live" without the addiction.