The odds have varied and there are exceptions (dont @ me) but very roughly about 1 in 45 to 1 in 100 total cards distributed in Magic booster packs will be a foil replacing a regular card
Sephara, Skys Blade In a deck with lots of small flying creatures, Sephara, Sky's Blade can come out extremely fast and for only upfront thanks to their pseudo-convoke
Whats the Commander Deck Size
For those formats, look to Atraxa, Grand Unifier, who has vigilance and deathtouch on top of flying and lifelink, and an almost-as-powerful card draw effect
With Zulaport Cutthroat, Blood Artist, or Syr Konrad, the Grim, this is a win condition
It really shines in +1/+1 counter decks where you can proliferate or put extra counters on this card and produce more ramp tokens