Not only can you play a cost 6 (or less) Song for free when you play him, but he also counts as a 6 cost character for playing other Song cards too, thanks to his Singer 6 keyword
You can give creatures you dont control -2/-0 until the end of the turn, you can create a taped Powerstone token, you can make a 0/0 Construct creature that has +1/+1 for each artifact you control or you can scry 1 and then draw a card
It will untap them if applicable and give them haste
The cards of Magic: The Gathering naturally come in a variety of rarities, ranging from common to extremely rare
Top 10 Cheap "Dragons" Changeling OutcastChangeling Outcast Metallic MimicMetallic Mimic Masked VandalMasked Vandal Universal AutomatonUniversal Automaton Korlessa, Scale SingerKorlessa, Scale Singer Shivan DevastatorShivan Devastator Scaled NurturerScaled Nurturer Mothdust ChangelingMothdust Changeling Reckless BarbarianReckless Barbarian Unsettled MarinerUnsettled Mariner And to be fair, they're right