Pair the vegetable, not the absence of meat.
Once you stop thinking of a vegetarian dish as a gap where the protein should be, it gets much easier. Roasted roots and squash have sweetness and body and take a fuller white or a soft red. Mushrooms are earthy and savoury and love Pinot Noir. Green vegetables, asparagus and fresh herbs want something bright and grassy.
Lentils, beans and anything slow-cooked will take a proper red without hesitation.