With G4's massive following, there are plenty of wonderful patterns to choose from to make a plushie in that style. There are even variations, including different body types, ponies who stand on two legs, chibi ponies, sitting ponies, laying ponies...
But what about previous generations? If I wanted to make a plush in an earlier style, where would I turn?
G1 had officially-licensed patterns by Butterick, with instructions to make Firefly, Moondancer, Blossom, and the wonderful, beautiful, amazing Starshine. I own one of these, albeit not a physical copy. They've got their own charm, but I'm looking for something with a more complex shape. Not too complex, just a bit more shapely.
Here's a wonderful (if lengthy) tutorial to make a pony that could look like a G1 (or maybe even a G3) with the right techniques, but the pattern calls for felt and I don't know how it would work with other fabrics. The pattern itself looks to be based on a Cabbage Patch style pony. The turning head is pretty cool, though!
https://www.youtube.com/watch?v=_DV6F3MH-EkThere's also this pattern that look like, with a bit of work, could look Midnight Castle-esque or even like a G2! It'd take more hair and a different eye style, but the shape itself works pretty well. It's a paid pattern on Etsy, so I'll just share the image so you can see what it looks like. It's segmented to allow for real horse markings, which is something cool you could do with it. You could also use a faux fur just above the hooves to make boys (or G2s)!
Those are both good options for G1s, but what other patterns resemble other gens? I'd love it if you could share, especially if you've done one of these up to look like a My Little Pony!
EDIT: Found another G1 pattern! this one's relatively simple, but does have a different shape to it. It's kinda tall.
https://www.youtube.com/watch?v=X7w3wBIKQKE