There are plenty of breeds that can do anything but I would make a couple points. First, not every individual of every breed can "do everything." Some poodles are great at dock diving and others won't set foot in water. Some border collies are great at herding while others have no interest in sheep. Some labs won't retrieve. A lot of it has to do with picking a puppy from lines that suits what you want to do with it. Even then it often fails. Many herding dogs are too nervy or reactive to compete in sports even when selected from agility lines.
Second, some dog breeds are jack-of-all-trades but masters of none. Poodles are one I would put in this category. Also some of the other retrievers. These are good dogs. If you're looking for a well rounded dog that you can do lots of different activities with, they're good choices. But they're not specialists and they're not going to be the best at doing anything.
Third, there's a saying in agility that the best dog for agility is the one you have. What this means is that you're better off working with the dog you already live with than going out and getting a dog specifically for a sport. You'll be more successful and have more fun working with a partner you already have a relationship with, and then maybe later after you know the ins and outs of your sport you can consider it when getting your next dog. Another saying is that when selecting a dog for agility, you want to pick the one you can live with for the other 23 hours of the day! It's true.
My recommendation, if you really want to get another dog to train and do sports with... is a labrador from working lines. I honestly think that they have the greatest chances of being both a dog you can live with and a dog that will excel reasonably well at most sports aside from protection sports and lure coursing. Labradors are low maintenance, and working line labs are drivey and perfect for dog sports. They are also the most popular service dog breed for a reason. They're harder to screw up than poodles are. Stonnie Dennis says working with working line labradors is similar to working with malinois in terms of their drive and trainability. Another thing about them is they're much less likely to exhibit behaviors that will cause you problems. Herding dogs tend to have protection instincts and are heavily influenced by movement. They tend to have more human wariness, excessive barking, car chasing, and child nipping. They're great dogs but may require more training due to these tendencies. I think it's better to stack the deck in your favor with a retriever. Possibly a golden, but it's much harder to find good working line goldens.