Dear Nicole,
Unfortunately, whether the pattern was free or not doesn't matter in this case.
All patterns are equally protected by copyright and may not be shared without the knowledge and consent of the respective author.
And even if it may not always be obvious at first glance, an author also gets certain benefits from free patterns that are connected with publishing them (e.g., advertising their own name or using them as a “showcase” for their own paid patterns or their own shop, etc.).
For this reason, only the author themself may decide how and through which channels their patterns should be available.
I hope this makes it a little clearer why distributing them by email is not only unfair, but also harmful to business (and therefore prohibited).
Apart from that, though, I just took a look, and here on Crazypatterns there are 77 results for the search term “hippo”:
Search: “Hippo”
Maybe there’s something nice there that could also be used for a mobile.
In any case, I hope you have fun browsing. :-)
Best regards,
Stefanie