The Machine by Concepit1
This three-part unbirth and belly-inflation story by Concepit1 on DeviantArt has the female main character, Frankie, have some fun with her recently finished «Machine». The machine had been built by her for her ultimate fantasies, and she was ready to try out all its functions.
Starting with a vore inspired session, she gets her machine to materialize a living Mew (from Pokémon) into her belly. Feeling the living creature moving inside her, and especially seeing her huge belly, she’s overjoyed to know her work hadn’t been in vain and everything was working like she wanted. The second thing she tries afterwards is with a Pokémon egg of a Bulbasaur, but instead of having that inside her stomach or so, she slowly manages to insert it into her own womb and the carrying out the entire «Pregnancy» of the Pokémon. During that she has some other fantasies, related to the chest-bursters from Alien, and her AI inside the machine comes up with some ideas…