Heat a large grill pan or use a grill. Brush the corn with 1 tbsp olive oil and season with salt and pepper. Grill over moderately high heat, turning, until crisp-tender, about 12 minutes. Let cool.
Heat 1 tbsp olive oil and 1 tbsp butter in a large skillet over medium-high heat. Add garlic to the skillet, and cook, stirring frequently, until fragrant, about 1 minute.
Add onion and cook until translucent, about 3-4 minutes.
Add zucchini, dried oregano, and thyme. Cook, stirring occasionally until zucchini is tender and cooked through, about 3-4 minutes.
Take the pan off the heat and stir in the juice of one lime. Let sit for a minute.
Working in a large bowl with an inverted ramekin, use a sharp knife to cut the kernels off the cobs in sections. Remove ramekin and transfer everything from the pan into the bowl. Toss to combine, add basil, and season with salt and pepper to taste.
Serve warm or at room temperature garnished with a few basil leaves.