Since I follow a ketogenic diet: bacon, eggs, beef, leafy greens, cheese (there's more to a keto diet than that, but I thought I'd stereotype myself)
Supplements include electrolytes, collagen powder, vitamin D.
I tend to ride after my work day. I have nothing to eat from about 2 pm and ride around 6. I take a bottle of water with me on a 20 mile ride and feel more energetic when my ride is over than when it started. For longer rides I may have a GU pack as back up, but may not need anything at all.