What’s a good source of breakfast protein for vegans?

Oats do it for me! I am not vegan myself but that's the only thing I eat in the morning. The night before I take 5mins to make my overnight oats: some milk (or any liquid really, soy milk or whatever) and I am done. In the morning I add fruits or nuts.

Pea/rice protein powder
Other protein isolates, e.g. hemp or almond protein
Soy products (if you’re not estrogen dominant!)
Beans & legumes

Eggs! I like making extra quinoa, bulgar wheat, or barley for dinners – and use the leftovers with breakfast. Soft cooked (runny yolks a must) on top and it’s excellent. All three of the grains bring additional protein to a good breakfast. To knock it “out of the par”, add some spinach or kale.

I like to eat porridge with oat milk and various yummies. My favourite is almonds, pine nuts and goji berries.
Another easy one is apples cut in pieces dipped in hummus.