Forager Organic Grain-Free O's are my absolute favorite gluten-free cereal option currently! Has a great sweet taste for such a low amount of sugar. I have it for breakfast or as a snack! 
Love love love this cereal. If you see it in your supermarket, give it a try!

Nutrition note: contains sunflower/safflower oil. 

Nature's Path Whole O's & Golden Tumeric cereals- another one of my favorites brands. Not all of their cereals are gluten-free, so make sure to read the boxes. The Whole O's have a pleasantly "sweet" taste with less than half the sugar content of most Cheerios varieties. The Golden Tumeric cereal is so tasty and has sweet coconut flakes that make it feel like a treat! Both ingredients super clean. 

Nutrition note: AMANDA APPROVED!

The Love Grown brand makes awesome gluten-free cereals. I love the Power-O's (it comes in plain, chocolate, and cinnamon!). This cereal has a bean-based flour for a little added protein as well. 

Nutrition note: the original flavor is completely Amanda approved; the chocolate & cinnamon flavors have sunflower oil.