What mix with a border collie would be more relaxed?

No one can tell you because mutts don't breed true. That's what makes them mutts and not purebreds. If you can't handle a border collie, don't get one. Find a breed whose personality you can live with. Looks should be secondary to personality/temperament.

None.

With a mix you never know what you're going to get. You could mix a border collie with a basset hound and still have a dog with a BC amount of energy. Also, with a mix you never know what the dog will look like.

Yes border collies are a stunning looking breed of dog. But if you can't handle the energy level I strongly suggest you consider a different breed altogether.

You never will know the personality of a mix breed or looks.

You can mix a border collie with the most calm dog in the world and the pups might still be as crazy as the border collie was. It all depends.

Aesthetics aren't as important as the breeds traits.

I wouldn't pick a Border Collie just based on it's looks. My Border Collie can run for days, and that's the reason I got him.

Choose a dog that fits better into your lifestyle, that should be the main reason for getting a dog.

Genetics don't work that way. You don't mix two breeds together and say "Now I want you to still mostly look like a border collie, but I want you to have less energy". Breeding mixes is rolling the dice. You get what you get

there's no guarantees that a mix would still look border collie, yet be relaxed.. it could still be just as hyper as a border, and look nothing like one.

NOTHING!!! IT"S A BORDER COLLIE!!

Do NOT buy this breed if you do not intend to spend at least 2 hours per day RUNNING. Border Collies do not settle with age.

With mixes, you can never predict temperment, trainability, looks, size, color or anything else. Its a chance you take. The dog can take after either parent, or something from both.