One of the Cosmoem you linked would fall into this category, but note that it's not a good example because 1) it's an evolved Pokemon, meaning it takes resources to establish, and 2) it's got a substantial retreat cost
In each case, during your upkeep you can copy a new creature, although this basically takes two mana to do so
The precon itself already offers some classic options, all of which are good enough to keep around if youre happy with them
This set will introduce new legendary synergy mechanics and full-art secret rares
While people who have been playing Magic for 20 years are loyal to the brand almost to a fault, for someone who picked up the game when Arena was officially released last month or a year ago during the beta, if Standard becomes unfun, Arena as a whole becomes unfun, and the easiest thing to do is look for a more fun way to spend their finite free time