I'm still working on my my monsters projects. I've finished seven. Two got given away as gifts before I could get pictures of them sadly. These two are going to cousins on Christmas Eve.
The fin on the orange guy was sewn the same way I sewed the fins on the turquoise dude. After I stuffed the monster, making sure to lightly stuff the fin thing, I sewed the dividing line between the fin and the body. Then I sewed down toward the body several times to create the fin definition lines.
I think the green slug guy is my favorite monster yet. I'm pretty happy with the monsters my kids have drawn for me. They are pretty easy to work from.