Well, I don't mean to take a different outlet on this topic but it didn't ask for characters that still had bodies so I can indeed tell you who I want brought back the most. This certain character, I, and most likely many others, would absolutely love to see again, although, I'm afraid that one of the only ways for her to talk to Littlefoot might just have to be in a sleep story of his if the writers go the traditional route with a character like this. Guessed who I am referring to yet? Unprovable bragging rights if you have already. I want Littlefoot's mother's spirit to make at least one more appearance. After all, she made a few already throughout the first movie. It would be great to get visible proof of The Land Before Time V: The Mysterious Island song lyrics that say, "You know I'll never leave you. You can find me anywhere".
Imagine what it would be like if in the second season it shows his mother's spirit again and he was able to talk with her about things. A sleep story would be the conventional way of talking to an angel/spirit/ghost/whatever she really is, or, I think it would be the most interesting scenario this way: What if during the first second season episode, Littlefoot does something to show that he has the purest heart or utmost virtue or something similar. After proving this, his mother's spirit, which I assume is in some LBT heaven/afterlife thing would have permission or gain the power to appear before him while he is awake at any time, but she can only be seen, heard, or touched by Littlefoot, and spirits of course don't have scents anyway.
Maybe she can't stay with him every second of the day or maybe not even every day. Maybe every once in a while he can call her mentally and her spirit will appear before him for a little bit and he can get advice, ask a question, or just have mother/son talks. And there would be two ways to handle this. Either she tells Littlefoot that it is best that no one knows about spirits like her, or she allows him to tell a select few, which should probably be his friends, as adults would either think he's is faking and is actually crazy. If he told his friends, I highly doubt they'd think he'd lost it, but more likely think he was faking it, but only at first, since that is what they thought he was doing in The Land Before Time IX: Journey to Big Water when he told them about someone that none of the others saw, until of course, he was able to provide proof.
I suppose my idea is very similar to the movie "Angels in the Outfield", except that I don't think Littlefoot should permanently lose contact with her in the end. Maybe a reason for a temporary separation again which could be something like, "she was out of time to be on Earth for now" or that "she needs to go back for a while and get her strength back". Since the first season episodes continued movies I-XII, why can't season two episode content, such as having access to his mother, be stopped with new movies? If this contact were to be established, I think movies made after the second season should continue the idea, as events such as Tria's appearance in The Land Before Time XI: Invasion of the Tinysauruses influenced all the movies made afterward so far. Another thing that would make this even more interesting: Let's say, Littlefoot needs a pure heart or utmost virtue or whatever at the time he wants to speak to his mother, and therefore, if he does something bad, his character is tarnished and he can't contact her again until he made his mistake right again.
And I have another view on this subject: What if you forget her being in spirit form when she is on Earth, but instead takes the physical form of living creature like a dinosaur, say, a young girl longneck around Littlefoot's age which anyone could see since she would have a physical body? She could be like Littlefoot's guardian angel. Those types tend to have huge hearts though and pretty much care for everybody. I could even see his mother saving a sharptooth's life because her heart knew it was the right thing to do, whether their kind killed her or not.
Now what if you forget my limited contact theory as well? What if after she takes the form a female longneck that is around Littlefoot's age and lives in the Great Valley. Then she is made an official new character of the gang, making it the gang of eight for however long she can be there. But since she still is a divine being, just in a "shell", it could make several story parts much more interesting if she had some kind of subtle special abilites that she could use to protect and help her son, his friends, other Great Valley resdients, and outsiders as well, flatooth or sharptooth, yet other than Littlefoot and maybe his friends, when amazing things happened, nobody else can explain how they did.
And then there is the humor. Littlefoot's mother will like to sleep with her family again, but would probably decide it's best that his grandparents remain unaware of her true identity. They could think of a true statement that doesn't reveal anything about her, and Littlefoot could say something like, "I met her a long time ago, we're realy close, she just moved to the Great Valley by herself, and needs a place to sleep. Can she stay with us?" which his grandparents would surely oblige. The humor can come in two ways. His grandparents would see how close they are, how they sleep right beside each other, and how Littlefoot would kiss her, as I am sure he would occasionally. Then his grandparents would assume that they were in love and make comments like "They sure look cute together" or "It looks like our Littlefoot found someone special." They might even ask her personal questions to see if she is Littlefoot's "type." The other form of humor would come from a young male longneck who likes his mother looks and so would flirt with her, like Rhett, Shorty, or someone new. When Littlefoot keeps stopping such actions, that would prove to his grandparents and friends (if his friends never learn the truth) that he is in love with her, even though it isn't that way at all.
One major positive would come from this: If she were to show up throughout the series in whatever form for whatever reason, we would surely learn what her name is finally. That would make some fanfictions easier. And speaking of fanfiction, if they don't bring her back, considering that there is a 99.99% chance they won't, it would always be nice to see something like this in a fanfiction, which anyone is welcome to use since I'm not nearly ready to start one yet.
And just like the "Who would you like Chomper to kill?" topic, I hope I didn't go beyond the perameters of the question again. This is just honestly who I want to see brought back more than anyone. Sorry if this idea is incredibly stupid, but it is all I could think of. And don't be afraid to straight up say "That idea is the stupidest thing I have ever heard" because I won't mind at all since that would be your honest feelings said in the most honest way you could. Nothing better than that. But if I can't give you permission to personally bash me here, you could always do so in a personal message which I will read and respect whatever you feel just how you feel like saying it. So relax and be honest since you can't hurt my feelings here. Later!