(1) Soy Milk or Edamame: Soy foods are health promoting. For example, they are protective: see Soy & Cancer. So among all plant-based milks, I prefer to add soy to sweet porridge for breakfast. Occasionally, I throw in some frozen edamame beans — they work out great in the sweet porridge.
(2) BROL: Another idea (which we can adopt in conjunction with the soy milk idea) is to use BROL recipe by Dr Greger. BROL consist of (B)arley, (R)ye, (O)ats and (L)entils in equal parts! Dr Greger prefers black lentils (beluga beans). Study BROL Recipes by Dr Greger. With BROL, we can prepare a sweet porridge like Tart and Tangy Cran-Chocolate Pomegranate BROL Bowl, or we can prepare a savory recipe like BROL Bowl with Sauteed Greens.
Instead of using this specific combination of whole grains and beans, we may devise our own combinations of whole grains and beans. But BROL is an interesting way to get started on such a journey.
(3) Sprouted Beans: Whenever I sprout whole grains and beans, I prepare a raw breakfast. Sprouted mung beans, sprouted 'kulthi' dal, sprouted 'moth' beans, sprouted black chickpeas ('kala chana') and sprouted adzuki beans go well with such a breakfast. For pics, see Sweet Porridge with Kamut, Sweet Porridge with Einkorn, Sweet Porridge with Spelt and Sweet Porridge with Rye.