The beauty of grain free is that you can usually feed less of it to keep your dog healthy, thus making it affordable. I'd try cutting back a little and see if that helps slim down your dog.
If you really want to switch, brands I like are that come in grain free varieties are: Taste of the Wild Pacific Stream, Pro Plan (grain free only - never thought I'd be saying anything good about Pro Plan - lol, but it's actually more expensive than TOTW in my area), Back to Basics, Victor, Acana, Now, Fromm, Farmina (Italian company - no GMOs used), and Dr. Tim's. Many of these are only available at specialty pet stores or online. Amazon.com and/or Chewy.com carry most of these.
Yes, there is grain-free weight control: Wellness Core Reduced Fat. Just make sure you feed the amount for what the dog SHOULD weigh (vet recommended weight, of course), rather than the current weight. Also, the suggested amounts on the bags are usually excessive, IMO.
Each dog is different, so what works for one dog may not work for another.