According to @py_rates, there are two more Blazers on the way including a "Black/Cone/Black/White" colorway in line with other upcoming Off-White x Nike additions such as the Air VaporMax, along with a "Canvas/Pale Vanilla/Black/Total Orange" makeup that strays from the rest with a vintage looking yellow upper.
The yellow-based style is rumored to kick things off this summer with a tentative July release, while the black version is expected to join the grey colorway in September.
UPDATE (04/16): In a recent Instagram post of the white Off-White x Blazer by Nike SB skater Hyun Kummer, Abloh left a comment confirming the existence of a black colorway. "Let me get you the black pair - Quick-Quick!!," Abloh wrote. This style is still expected to release in September.