Whisk oat flour, buckwheat flour, coconut flour, and flaxseed meal together in a small bowl. Pour in almond milk and kombucha; mix well to form a sticky batter. Set aside to soak in a warm spot in the kitchen, 8 hours to overnight.

Blend batter with banana, baking powder, and baking soda until combined.

Heat oil in a large skillet or griddle over medium-high heat. Place 1/4 cup of batter in the skillet and cook until bubbles form and the edges are dry, 3 to 4 minutes. Flip and cook until browned on the other side, 2 to 3 minutes. Repeat with remaining batter.