Brian May says there's a chance of his collaboration with Tony Iommi coming out.

[Scott]

Honestly, a box set of new/unreleased Iommi riffs would be pretty swell.

"That’s right! Obviously there have been rumours of collaborations between you and Tony for a long time. Is there any chance that could still happen?"

“I think there is a chance. We do more talking than anything else, but we do a lot of talking. He is really my dearest friend in the business and has been for so many years. I could write books about Tony because he’s just the most [pauses]... I don’t even know how to put it into words. You know, he’s a luminous human being is Tony, with a wonderful, kind nature and an incredibly baffling sense of humour."

https://www.guitarworld.com/features/brian-may-i-will-never-claim-to-be-a-great-guitarist-in-the-sense-of-a-virtuoso-i-just-try-to-play-from-my-heart

[Charger]

Interesting.

It would be kind of cool to hear what May and Tony have come up with...but unless they are finished songs I can't see this coming out. I don't think there's a lot of market for stuff like that.

[Jack the Stripper]

It would be fascinating to hear what they’ve come with. I’ll take absolutely anything at this stage. It’s a travesty how little new material we’ve had from Tony the last 20 years.

[Zzzptm]

Heck, I'd even spend 2-3 minutes listening to them tuning their guitars!