I've found out I can tolerate half a red grapefruit so, when I'm eating breakfast, that is my current favourite.
Sometimes I'll have raspberries with greek yoghurt, eggs, bacon, sausages, mushrooms, a Lidl roll bacon butty and - a real treat this - a visit to a Toby carvery for one of their really lush breakfast all you can eat buffets - just avoid the potato hash, yorkshire puds and toast.
If you need cold breakfast ideas then you could pre-cook some low carb sausages and bacon and make a breakfast type omlette the night before to eat hot or cold - same with crustless quiche.
You never know, you could be one of the lucky ones who can tolerate porridge - do a blood test before eating the porridge then again two hours after - I used to love porridge and muesli but doing that test put me off eating any kind of oat based meal completely.