I like a good pasta sauce. this is my go-to.
Heat up a frying pan with olive oil and add diced onions until soft. toss in some diced garlic and chili flakes, let cook for about a minute while stirring then dump in a can of crushed tomatoes. I use unsalted then add salt as needed. With the salt I'll add a bit of sugar, basil, more chili flakes, tasting along the way to adjust as needed. From there I'll mix it up depending on what I'm feeling. Possibly throw in some roasted red peppers (I remove the skin and rough chop), maybe spinach right at the end (just long enough for them to wilt, any longer gives the sauce an earthy taste I don't like), sometimes some pomegranate vinegar to give it a tang. Just experiment a little. If it gets too thick for your liking add a bit of pasta water to thin it out.
As mentioned if you want full flavour make the sauce the day before and leave in the fridge overnight. Then heat back up on the stove before serving. The day in the fridge makes it a whole different sauce. I'll usually make enough for that night and the next for that reason.
A lemon caper sauce is also a favourite. It's super easy and great for chicken and pasta dishes. Actually had it last night. Threw some chicken thighs on the bbq with salt and pepper until just done, then tossed them in the sauce and served on rotini (also tossed in the sauce). So good.