The flexibility of this card is unmatched by previous iterations of this effect, and that's why I believe it'll be a cornerstone of Blue-based Control decks until it leaves the format
Serra Angel In the early days of Magic, a clean, powerful creature with no downside was a big deal, and Serra Angel was exactly that: a 4/4 flier for 5 mana that also has vigilance, meaning it can attack and still stay back on defense
The graphic they added to the Mystery Booster packs had a square background, and the one they used for The List seems to have a rounded background, which creates a telltale difference in the shape of the cards border as you can see on Chatter of the Squirrel and Ancient Den as well as subtle changes in its placement on new border cards, as seen on Boros Challenger
It isnt the only card to break out of a specific inks identity, but at such a low cost it has a large impact
The amount of tempo you get when playing this card is unmatched
While there is no one rule for determining land count, it's crucial to know where your average mana cost is and take it into account when deciding this