Motherlode inhabitants
The planet Motherlode was inhabited by several species of heavy metal miners. 

During his visit to the planet in 2269, Harry Mudd referred to these individuals as both shrewd and intelligent, as he attempted to sell them a bogus love potion. 

After it was revealed to the miners that they were being duped, they began to riot and throw rocks at Mudd. ()

Unnamed

Alien  

This humanoid miner was among the crowd Harry Mudd to whom was selling his love potion. ()

Human  

This Human miner was among the crowd Harry Mudd was selling his love potion to. 

Skeptical, this miner wondered how much the potion would cost, only to scoff at the price Mudd offered it for, three hundred credits. This miner then told James Kirk and Spock to keep out of their business dealings with Mudd, after the two Starfleet officers attempted to arrest Mudd during his sales pitch. He then promptly told Mudd that they had a deal and that he would purchase the potion from him, but quickly became angered when Spock revealed to him that Mudd was tricking them. 

The miner then threatened to shoot Mudd with his sidearm but was repelled when Spock used his phaser to blast a trench between the miners and themselves. ()

Ursinoids

Female 

This female Ursinoid miner held back the angered male Ursinoid as he lunged towards Harry Mudd, after Mudd's implied comment about his race being repugnant. She later demanded proof from Mudd to support his claims regarding the love potion. ()

Male  

This male Ursinoid miner was angered when Harry Mudd made the generalized statement about the miners of Motherlode as being either "young, old, fat, ugly, or repugnant," a statement on which Mudd quickly backpedaled, stating that it was "nothing personal". ()

Unnamed Humans
Motherlode inhabitants
Unnamed² species
 Motherlode inhabitants