The most popular guess seems to be Kanye West, and there may be visual evidence proving this theory to be true.
Some think it could be Asahd, who already has an executive producer credit under his belt.
Most of all, people just want Migos to release the album already.
In the meantime, we should expect to hear some new music from Migos any day now, after Quavo alerted fans last week that a new single would be dropping "soon."