Interestingly, about one in 8 Collector Boosters will have a mythic of some kind in slot 4, but because theres so many variants, each individual one will be quite rare
All of the above creatures were in my first cut of the deck, but some were pulled on space as I preferred the consistency of early plays like Precinct Captain, Preeminent Captain, Whipcorder, and Brimaz, King of Oreskos to have a quick board presence, and then leaned on Sliver-esque Lords that would grant stuff to my team for the rest of the deck
Use the toughness of the creature as it last existed on the battlefield to determine how much life to gain
Occasionally some decks will require more, while some formats (or deck archetypes) feature enough mana acceleration and cheap spells that they require less
Those decks are hard to make work given how much lifegain there is, but as decks get lower to the ground, this will get better
Offensively it is very much the same level of game over when you start to get your attack on