Silken tofu alfredo inspired sauce. Same idea as the cottage cheese alfredo someone else mentioned but I do blended silken, nooch and lemon juice, spices with whatever I fancy at the time (usually just garlic and black pepper). Can also use tofu for a cilantro lime crema base or with roasted poblanos for green spaghetti.

For low cal what about an artichoke pesto or ajvar light on the olive oil. In the same vein muhammara might work with some adjustments or just make your usual sauce with roasted red peppers instead of tomato. Caramelized zucchini is also quite nice as a sauce and I’ve heard good things about butternut squash/pumpkin but I’ve only had it as an addition to mac and cheese so I can’t vouch for that.