The easiest master sets are smaller, currently in-print sets where singles are cheap and widely available
You can obtain the Arven (2-Diamonds rarity) card by opening Paldean Wonders from Paldean Wonders set
Not only that, but it's a continuation of a song, and it's quite beautiful to boot
If only there were a way to overcome that annoying Fighting weakness And guess what

Acid-Spewer Dragon Adult Gold Dragon Akoum Hellkite Akul the Unrepentant Alabaster Dragon Amareth, the Lustrous Ambitious Dragonborn Amethyst Dragon Ancestor Dragon Ancient Brass Dragon Ancient Bronze Dragon Ancient Copper Dragon Ancient Copper Dragon Ancient Gold Dragon Ancient Hellkite Ancient Silver Dragon Ao, the Dawn Sky Arashin Sovereign Arcades Sabboth Arcades, the Strategist Arcbound Whelp Archive Dragon Archwing Dragon Armament Dragon Artificer's Dragon Ashmouth Dragon Astral Dragon Atarka, World Render Atsushi, the Blazing Sky Avaricious Dragon Avenging Hunter Backdraft Hellkite Bahamut, Warden of Light Balefire Dragon Beledros Witherbloom Belltoll Dragon Betor, Ancestor's Voice Betor, Kin to All Bhaal's Invoker Black Dragon Bladewing the Risen Bladewing, Deathless Tyrant Blast-Furnace Hellkite Bloomvine Regent Blue Dragon Bogardan Hellkite Boltwing Marauder Bone Devourer Bone Dragon Bonehoard Dracosaur Boneyard Scourge Boulderborn Dragon Brainstealer Dragon Brimstone Dragon Broodcaller Scourge Broodmate Dragon Broodmate Tyrant Caldera Pyremaw Canopy Dragon Canopy Gargantuan Capricious Hellraiser Catacomb Dragon Cavern-Hoard Dragon Chaos Dragon Chardalyn Dragon Chiss-Goria, Forge Tyrant Chromium Chromium, the Mutable Clarion Conqueror Clockwork Dragon Cloud Dragon Colossal Grave-Reaver

In particular, if you search for Meklord Assembly and destroy this card with its effect, you will be able to recruit "Meklord Monarch" monsters ignoring the summoning conditions, even with conditions and restrictions, due to the effect of (3)