This is a free product so take what I have to say with a grain of salt.
So, apparently this is collection of monsters featured in other Lesser Gnome products. I downloaded it having never bought or read a Lesser Gnome adventure. My hope was that maybe they had some interesting or unique creatures inside, but alas most of the book is full of random generic creatures covered in just about every monster manual ever. This leads me to think that Lesser Gnome does not traffic in new or interesting twists on D&D, but rather is just another publisher of fantasy PDF spam.
TLDR; Get this title if you have several Lesser Gnome product and want all the monster stats in one easy place. Do not get it if you are looking for unique or interesting monsters.