Here are a few sweater options you could use to embroider your own sweater:
This sweater is available in lots of colors and sizes (0-3 to 5T). Unfortunately not always available on Amazon with free shipping, but worth it in my opinion. 
This green sweater is also available in lots of colors and sizes (0-3 to 5T). Similar to the sweater linked above, but sold by another vendor and worth checking out to find the best deal.
This is an oversized knit romper. Definitely a bit oversized, but I personally love that look for little toddlers. Available in multiple colors and sizes:
Another great quality sweater option linked here. Available in gray, beige, and pink - sizes 0-3 to 4T.
Learn how to embroider your own sweater with this Stitch Along tutorial!
