I've helped lots of abandoned cats in my lifetime. Every cat I've ever kept has been either adopted or born a stray and tamed by me.
I found a beautiful longhair cat a couple of years ago, and she was starved. I just happened to be bringing in some groceries at the time, so I popped open a can of cat food for her and let her have it. She came back time and time again, and one day we realized she'd gained some weight and that she wasn't just getting furrier... (You know where this is going.) Yeah, she brought us four baby kittens, one of whom still lives with me.
I've also raised a litter of five young feral kittens. Their mother was cared for by a man who had done work for PETA and who worked at the hospital. The cats lived in the forest and the man would feed them. One day, he had the mother spayed and adopted out, but he didn't know that she had babies in the woods. We eventually captured them all, hand-fed them the KMR, and adopted them out when they were older. It was kind of sudden, but I liked them a lot and was glad to help them.
There was an adult cat who used to roam around our neighborhood, and he despised people. He had this limp, and I think he'd probably broken his leg and let it heal on its own since he feared people so much. My neighbor called him the Old Man, so I called him Man. One day, I walked outside to feed Cat and Yippy (the first cat that I mentioned and her daughter) and Man was lying under the table where the food dishes were. I walked over to him and thought he'd run, but he didn't. I eventually got close enough to pet him, and then I poured some food for the three cats and left. My neighbor was surprised by the story, and really didn't believe it until she saw the same thing happen again. Since I could finally get close enough to Man for long periods of time, I could look at him. His paws were raw, his coat was rough, he had scratches, and his skin was funny. I really can't describe his skin, it was just kind of strange. He had a lot of bald patches. I eventually was able to wrestle him into a cat box (He was okay with the petting, but he wasn't about to be shoved into a little cage!) and take him to the vet. I knew what was going to happen, but I made it go to the back of my mind. The vet examined him, and told us that he was just too sick to go on with his life. That was probably why he'd turned to a human for help, in my opinion. I let the vet euthanize him that day, and then he was buried in the huge field bordering the woods behind the vet's office.
I also took care of a little kitten whose mother abandoned her in the middle of a hurricane. She was nearly drowned, so I tucked her in my coat and brought her to the house where she could get warm. I fed her some KMR (After all these tales of abandoned kittens, don't you expect me to have an emergency supply in the kitchen? Hahaha.) and she sucked it out of the eyedropper like she'd never eaten before. We thought she was going to die several times because of how small she was and how she'd already almost drowned (My uncle said she might die of a cold or pneumonia.), but she grew to be a small, sleek, beautiful adult. We named her Isabel, after the hurricane that could've killed her, and I swear that she was the most intelligent cat (or possibly animal) that I've ever met in my entire life. She talked to us as if we could speak her language. I don't recall her meowing much. She was a brilliant chirper. When she wanted food (usually things she shouldn't have, such as pizza--one thing she loved), she let out a long, loud chirp. When she wanted to play, she let out another chirp. When she wanted to go out, you guessed it...she chirped. She looked people in the eyes and I could tell exactly what she was thinking. She even taught us how to throw tiny foam balls for her to fetch. Isabel would grab the ball in her mouth, carry it over to her person of choice, sit the ball by the person's feet, tap the person's leg, and chirp. The chirps got louder and the taps grew more frequent if you ignored her request. It was hard to resist, though. Once the person threw the ball, she would chase it no matter where it went. If it hit one wall and went the other way, she'd turn on a dime and get it. If it was out of her reach, she sat and thought until she had a solution. Once she had the ball, she would carry it back to the person and drop it. If one person got tired, she found another person. Once, my cousin, sister, and I took turns lying on the floor and making a hurdle course for Isabel to run over. One of us would throw the ball across the room, and Isabel would take off and jump over each person before catching it. She was great. Isabel always had her morning routine of going outside for a run. Sometimes I'd take the ball out and we'd play fetch outside. Usually she'd just go exploring, though. One day, Isabel didn't come back. She was usually pretty prompt about coming back when we called her, so we were worried. We found her on the road. She had been hit by a car, and was already dead.
I know they aren't all exactly "touching" stories, but I had a good time thinking about each of the cats :) I miss 'em all...