Blue Sun's Zenithcard_drawBudget$4.59Very close functional match: scalable instant-speed card draw that targets a player and draws X cards, with the upside of shuffling back into the library.
Stroke of Geniuscard_drawBudget$0.33Classic analog to Braingeyser that draws X cards for any target player, with the same flexible scaling and a slightly different table impact.
Mind Springcard_drawBudget$0.54Straightforward scalable blue sorcery draw spell that trades the targeted player clause for self-draw, filling the same X-draw role.
Pull from Tomorrowcard_drawBudget$1.98Efficient scalable instant card draw that serves the same late-game mana sink role, though it only draws you the cards.
Pondering Magecard_drawBudget$0.13Not a direct equivalent, but a blue value draw spell that can generate extra cards in a similar control-shell context when you want scalable card advantage.
Jace's Ingenuitycard_drawBudget$0.05Budget-friendly instant-speed card advantage spell for blue control decks, providing raw cards in a similar role though not scalable.
Tidingscard_drawBudget$0.22Simple sorcery-speed draw-four effect that sits in the same family of blue card-advantage spells, albeit without X scaling.
Recurring Insightcard_drawBudget$1.28Late-game card draw engine for blue control decks; while not X-based, it often produces a very large burst of cards comparable to a big Braingeyser turn.