Here are several examples pulled from EDHREC's artifact theme: Oooh, I like that last line of text
Like Saheeli she has a second ability, where at the end of turn you can spend any amount of energy, to make a vehicle token with power and toughness equal to the energy spent, and crew 2 While Pia Nalaar has potential in more aggressive decks, shes much narrower that Saheeli, and Living Energy is built to work with Saheeli in charge
Nissa gives you value right away, she adds to the board, and she represents a late game threat that needs dealing with and she does all this without ever costing anything above the three mana you pay for her
You can generate a bunch of mana with green, draw a bunch of cards with blue, then deal a bunch of direct damage with red, with some nice crossover between all three in the middle