ENHANCE TREE - BEST WAY

Anyone have a good strategy for make grade S monster ??
I have try to Enhance all the monster that i have catch (Common - Uncommon - Rare) and the best grade that can be my monster is A- !!
So how for have monster at grade S ???
What is the best way for have a lot of monster to enhance for increase the grade of my monster ??
Thank to all !!

to get monsters s you use blobs.

Blobs are rare to found !!! So need a lot Of time for found them ! )

I think the problem is not what monster should we use for enhancing. The problem is how do we earn lots and lots of silver to do the enhancing. I have lots of blobs. Yeah so what? Each blob requires me at least 100k of silver to enhance my monsters. I have blobs but not the silvers. LOL.

So point is how do we earn silvers fast?