DVD Box Sets for the 3rd and 4th Season have been announced

Cardfight Vanguard G NEXT DVD-BOX (Part 1)

Release Date: May 23rd, 2018

Price: 10,000 Yen

Contains:

25 Episodes

A Special Character Song CD centering on Jaime Flowers

Promos Signed by their Voice Actors:

Ranunculus of Phantasmic Blue, Ahsha

One who Proceeds Towards Daybreak, Scharhrot

Battle Sister, Florentine

Creditless OP and EDs

Cardfight Vanguard G NEXT DVD-BOX (Part 2)

Release Date: June 27th, 2018

Price: 10,000 Yen

Contains:

27 Episodes

A Special Character Song CD centering on Fukuhara High School Vanguard Club

Promos Signed by their Voice Actors:

Higher Deity Knight, Altmile

Black Shock Gavrail Prime

Dragonic Vanquisher “SPARKING”

Creditless OP and EDs

Cardfight Vanguard G Z DVD-BOX

Release Date: July 25th, 2018

Price: 10,000 Yen

Contains:

24 Episodes

A Special Character Song CD centering on Striders

Promos Signed by their Voice Actors:

Chronojet Dragon Z

Dragfall, Luard

Golden Holy Sword, Gurguit

Creditless OP and EDs

Each of these, if ordered from Amazon, comes with an exclusive Soundtrack CD, apparently.

Source