Generically, I am opposed to sets of things, unless they really NEED to be a set, like a set of measuring cups or spoons. But a set of cookware is usually a few useful pieces with some other things that you will never use, put together to sell more cookware total, at a lower cost per piece. But since you don't use all the pieces, it isn't a real savings. And note that a wall of pots that all match has no value in my world. If it does in yours, then you can increase the value of a set.
With all that in mind, there are a few sets I have come across that make sense from both a financial and usage standpoint.
The first and most surprising is from Sam's Club. I just got a 15 piece set of anodized aluminum Member's Mark cookware. We are in process of moving from Texas to Cleveland, so my "good stuff" is at home in Texas, not at home in Cleveland. I was going to pick up a few pans and maybe a pot, and I like Sam's Club for their restaurant grade stuff (the restaurant supply store was closed...Christmas eve). I was nearing the cost of the 15 piece set ($150) with the pieces I had picked out and still didn't have any lids. The heft on the pieces is good, the handles are well made and attached well and there isn't a piece in the batch that I won't use someday.
The only downside for me is that all the cookware has non-stick coating, although they claim that it is harder than usual. However, there are many people who WANT non-stick everywhere, so that might not be a down for you. I would just advise you to check it out yourself. Sam's is noted for changing the item that fills the needed niche. They have had other aluminum sets in the past that I wouldn't touch. This was a pleasant surprise.