It's possible. Fanfiction communities often have a wide variety of stories. Look for platforms that have a reputation for moderating content well. You can also join relevant fan communities and ask for recommendations. They may be able to point you towards well - written and appropriate 'Toriel pregnant' fanfiction that adheres to the general spirit and lore of the source material.
Yes, there might be some out there. However, you should be cautious when looking for fanfiction. Some platforms like Archive of Our Own (AO3) could be a good place to start. You can search using the relevant tags to find stories related to Toriel's situation in a more family - friendly or appropriate way.
There could be. You can try searching on fanfiction - specific websites. Check for tags like 'Toriel' and related family - centric or positive story tags. Make sure to read the summaries and ratings to ensure it's something you're interested in and suitable, as not all fanfiction in this area may be of high quality or appropriate for all audiences.