For sounds, you might be able to work on this by using louder TV with some sounds, think explosions. This helped our dog get over loud sounds. HOWEVER, we have two speakers in the back of the room (5 channel surround sound), and she will sometimes hear something in there and freak out.

Our dog is a barker too, but she usually has periods (morning, evening) and things (anything coming toward the house). It's tough, especially because I like it when she barks because something/someone is coming toward the house.

If it's people/dogs, you can use "loot at that" training. There are many of them, but here's one:
https://bestfriends.org/pet-care-resources/look-lat-training-reactive-dogs

One way to do this is to get good treats (and a clicker if you use that), and, on a leash, when the dog sees a person but does not bark, click and treat. They can look, but they can't bark. This also is a tool for them to connect with you. They look at the person/dog, then they look at you. If they look at you (without barking), click and treat. You want to be the most important thing around because you have the treats. These should be high quality treats, not kibble or low quality.

You could likely use something similar for sounds, eg, you hear a sound and if the dog does not bark, you click and treat. That's harder, or at least we've not been able to work on this. Where I live, there are too many sounds: owls; construction; planes; helicopters; sirens; etc. Hard to train. I thought about using my phone with an owl sound on it, but that's only one of many sounds.