Creatures you control gain that ability until end of turn
You should also know that by increasing Esper Sentinels power, it becomes harder for your opponent to pay the mana tax, making it more likely that theyll let you draw cards

Admonition Angel Adventuring Gear Aesi, Tyrant of Gyre Strait Akoum Firebird Akoum Hellhound Akoum Hellkite Akoum Stonewaker Ambrosia Whiteheart Architect of the Untamed Attercop Avenger of Zendikar Baloth Woodcrasher Belligerent Whiptail Beorn's Hospitality Black Chocobo Bloodghast Boughside Wanderers Bristly Bill, Spine Sower Brushfire Elemental Calcite Snapper Canopy Baloth Canyon Jerboa Caustic Crawler Choco, Seeker of Paradise Chocobo Racetrack Claim the Kingdom Cosi's Ravager Courser of Kruphix Dancing from Dark to Dawn Down in the Valley Dragonback Assault Dreadwurm Druid Class Dnedain Rangers Earthbender Ascension Elfsworn Giant Elven Raft-Steerer Embodiment of Fury Embodiment of Insight Emeria Angel Emeria Shepherd Eternity Vessel Eumidian Terrabotanist Eusocial Engineering Evolution Sage Fearless Fledgling Felidar Retreat Fledgling Griffin Floral Evoker Gandalf, Shadow's Foe Genemorph Imago Geode Rager Geyser Glider Geyserfield Stalker Glacier Godmaw Gladiolus Amicitia Glyph Elemental Grappling Kraken Grazing Gladehart Greensleeves, Maro-Sorcerer Groundswell Grove Rumbler Guardian of Tazeem Guul Draz Overseer Hagra Crocodile Hedron Crab Hedron Rover Hedron Scrabbler Icecave Crasher Icetill Explorer Ior Ruin Expedition Iridescent Vinelasher

You'll probably want enchantment creatures and artifact lands in Winter's deck, as well as some really big cards you can suddenly reanimate to terrify your foes
When viewed in this light, Dominaria United Jumpstart is superior in every way to what Theme Booster packs were
Malignus comes into play for five mana, and its usually somewhere between a 15/15 and 20/20 at least