Deep-Cavern Bat Cards with similar effects have been printed through the years, such as Brain Maggot, Kitesail Freebooter, and Mesmeric Fiend, but judging only by its stats, Deep-Cavern Bat does a way better job than the others, as a flying creature is harder to block and has lifelink to help against aggro decks
They're legendary in the game
Delighted Halfing provides an additional Cavern of Souls style protection from counterspells on key legendary spells, of which this deck has plenty
Ringsight You're in deep if you have Ringsight
Then the eight-cost Sultai sorcery will destroy all dorks and enchantments but then you'll draw equal to what you lost
Counterspells like Essence Scatter can target a creature while its on the stack, but they cant target a creature thats already on the battlefield because its no longer a spell