Make sure to watch the video for some more examples, and if you have any questions, make sure to let me know in the comments
Even without Quantum Riddler, blinking Thundertrap Trainer allows you to grab a noncreature spell and draw an extra card because it's an Otter

Abdel Adrian, Gorion's Ward Acolyte's Reward Ancient Greenwarden Angelic Reward Artifact Ward Atraxi Warden Attentive Skywarden Auriok Bladewarden Bahamut, Warden of Light Baird, Steward of Argive Black Ward Bloodsworn Steward Blue Ward Boromir, Warden of the Tower Boseiju Reaches Skyward Broodwarden Cleric of the Forward Order Coward // Killer Coward // Killer Cowardice Crowd-Control Warden Cubwarden Curator's Ward Dawnhart Wardens Death Ward Denethor, Ruling Steward Duchess, Wayward Tavernkeep Edward Kenway Enduring Bondwarden Ephara's Warden Esior, Wardwing Familiar Essence Warden Fairgrounds Warden Faith's Reward Faramir, Steward of Gondor Fast Forward Final Reward Flickering Ward Gallows Warden Gandalf, Westward Voyager Gavi, Nest Warden Ghalma's Warden Ghost Warden Ghost-Lit Warder Goblin Coward Parade Goblin Wardriver Goldwarden's Helm Goldwardens' Gambit Green Ward Greenwarden of Murasa Grenzo, Dungeon Warden Guildscorn Ward Heart Warden Hixus, Prison Warden Homeward Path Honor's Reward Ifrit, Warden of Inferno Jadzi, Steward of Fate Jor Kadeen, First Goldwarden Kangee, Sky Warden Kavaron Skywarden Kin-Tree Warden Knight of the Skyward Eye Kopala, Warden of Waves Leonin Relic-Warder Liliana's Steward Littjara Glade-Warden Look Skyward and Despair Lukka, Wayward Bonder Lumengrid Warden Merry, Warden of Isengard Nemata, Primeval Warden

Since theyre all from disparate worlds and games, they each do pretty distinctive things with little common ground, but nonetheless its possible to build a fun themed deck around cramming in a bunch of final bosses