Both dogs my family has owned have been mutts, but it also happens to be that some of the possible breeds that have been part of the mix are my favorite.
But, I love:
Labs, German Shepherds, Huskies, Boxers, Australian Shepherds
The first dog my family had, was a true mutt of mutts. Still no true idea what was in her, but she lived to 17, and only because we put her down. Her heart seemed strong and she still had energy bursts, but her kidneys were failing, and likely a lot of her body was too. She was getting really thin (although she was pretty thin her whole life), and her hips were starting to cause her problems unless she was in an energy kick. Was so hard to accept that it was time to let her go, for her own good - she was generally slow at that point and just wasn't herself, especially her last year. Heart didn't want to stop though and never showed signs of heart trouble.
Probably had some terrier, standard poodle (the big kind - those are so cool), but who knows what else.
Current dog: Known to have Lab, a hint of Rottweiler (doesn't show, her mom had a little, and the previous generation dad was probably even mix lab/rott), and most likely a great deal of Aussie Shepherd. She seems like an even mix Lab and Aussie. Boy is she fun. Has a Lab coat, but is kind of small, roughly 40lbs and about the size of an Aussie iirc. Has the face of an Aussie with some Lab. Has an even mix of personality too. Quite a lab, but the energy, spirit, and antics of an Aussie. Has different bonds with different people, very loyal, defender of the yard and any random movement, sometimes I swear even just a shadow outside, gets her all worked up. Takes awhile to warm up to strangers but never is threatening when we're home, at least she's probably never felt threatened by anyone that's come in, just not fond until she has time to warm up to them. After that, it's play, jump, lick, and maybe hump. She's a humper. :laugh: And she was fixed. She very much wants to be the Alpha Female.