Another vote for hard boiled eggs or quiche- to make life even easier search recipe forum for "egg muffins." It's the same thing- meat, cheese, veg and eggs but some in a muffin tin, so you can grab and go. I prefer these cold, but you can microwave them to hear them up, as well.
Also, you can make a cheese and egg scramble in the microwave- just use a giant mug or it will overflow!

A very popular recipe here is the muffin a minute. There are endless variations but basically it is Flackers or almond or coconut flour, an egg and flavors of choice. I'm a minute flat, you have a muffin. Add some butter or cream cheese and you are set.

I like to make "granola" sometimes with a variety of nuts, seeds and coconut shreds. You can also eat this with almond milk or cream thinned with a little water.

Cottage cheese is also great if you get tired of the yogurt.

I know the granola and egg muffins require work the day before, but you can make a week's worth in 30 minutes at the most.