By the Grace of the Gods 09 (Manga)

Slime's up for one recently deceased middle-aged businessman! When the gods reincarnate him in another world as a boy with magical powers, he discovers that magically tamed slime are an untapped natural resource!
A Slimy Conspiracy!
Ryoma’s life in his new world has been blessed by many encounters with wonderful people, but lately malicious miscreants have been invading his otherwise blissful existence. The laundry shop’s success has seemingly attracted more mischief-making thugs, but there appear to be hidden motives behind the actions of these troublemakers. After some investigating, it seems a major faction of the Tamers’ Guild may have it out for Ryoma!