The most obviously powerful one of these is Syvelun of Sea and Sky, which is basically an indestructible merfolk that draws cards and helps protect your other creatures
Lurrus shines in low-to-the-ground decks with lots of 1- and 2-mana cards, usually aura decks in Historic
Any good re-imagining of Athens has to feature a grand monument or two, and Meletis is no exception
Looking at midrange all-stars like Den Protector and Sylvan Advocate, its easy to see what makes a good midrange card: efficiency or guaranteed card advantage
From Dissension to Today Moving forward, Eventide introduced several white/black creatures with lifelink (a keyword which had only been introduced the previous year in Future Sight): Voracious Hatchling, Nip Gwyllion, Nightsky Mimic, and Divinity of Pride
And at the beginning of each end step, if any creature card was put into your graveyard that turn, he creates a 1/1 Devil token that deals 1 damage to any target when it dies