While it was previously possible to treat Synchro Monsters as Tuners using cards such as "Lightwave Tuning", "Psychic Tuning", etc., printed Tuner Synchro Monsters were first introduced in Starstrike Blast.
In the anime
In the anime, Tuner Synchro Monsters are required to perform an Accel Synchro Summon, a method of Synchro Summoning that uses Synchro Materials that are themselves Synchro Monsters. A monster Summoned by such a method is known as an Accel Synchro Monster. All Accel Synchro Monsters possess an effect in the anime that allows them to be Summoned during the opponent's turn.
In the TCG/OCG, all Accel Synchro Monsters were changed to regular Synchro Monsters, and their inherent effect that allowed them to be Summoned during the opponent's turn was removed. However, certain Tuner Synchro Monsters instead have an effect that allows the player to conduct a Synchro Summon during the opponent's turn, as long as it was one of the Synchro Materials used. In this way, those two monsters could be used to Summon any Synchro Monster during the opponent's turn, rather than just Accel Synchro Monsters.
Tuner Synchro Monsters
|Celestial Double Star Shaman||天輪の双星道士||LIGHT||Fairy||2||100||800|
|Denglong, First of the Yang Zing||源竜星－ボウテンコウ||LIGHT||Wyrm||5||0||2800|
|Flower Cardian Moonflower||花札衛－月花見－||DARK||Warrior||6||2000||2000|
|Life Stream Dragon||ライフ・ストリーム・ドラゴン||EARTH||Dragon||8||2900||2400|
|Battlewasp - Azusa the Ghost Bow||Ｂ・Ｆ－霊弓のアズサ||WIND||Insect||0005||00002200||00001600|
|Life Stream Dragon||EARTH||Dragon||0008||00002900||00002400|
|T.G. Wonder Magician||ＴＧ ワンダー・マジシャン SCX-1000||LIGHT||Spellcaster||0005||00001900||00000000|
|Celestial Double Star Shaman||天輪の双星道士||LIGHT||Fairy||0002||00000100||00000800|
|Stardust Spark Dragon||LIGHT||Dragon||0008||00002500||00002000|
- Many of the "Assault Blackwing" Synchro Monsters, such as "Assault Blackwing - Raikiri the Rain Shower", have effects to treat themselves as a Tuner.