Personally, I like to juice up several different kinds of fruit and vegetables - which may include various combinations of bananas, red bell peppers, apples, carrots, celery, broccoli, spinach, parsley, tomatoes, cucumbers, etc.
I'm obsessed with broccoli, carrots, celery, string beans, snap peas, black kale, brussels sprouts, cabbage - I could go on! They used to call me 'rabbit' when I was a kid. I hate mushrooms, though. I apologize to fungi lovers, but this way, there's more for you!