The right billionaire / fringe group / clandestine evil organization could do something interesting with Bir Tiwal, the largest expanse of unclaimed land in the world.[0]
In the interests of being pedantic, the slice of Antarctica that no one has any claims in is the largest expanse of unclaimed land on Earth, and it has the advantage of being actually unclaimed.
Bir Tawil and the Danube pockets are claimed, it's just that the border disputes mean that both parties argue it's the other side's claim; should the border dispute get resolved, there will be a clear owner of the land.
This is like Liberland in the Balkans. It's not "unclaimed and no one wants it". There are two drawn lines for the border. Each country prefers a different line, which gives them better territory and the other country Bir Tawil. Neither country will tolerate a third party coming in and claiming the land.
How are they intending to get to Bir Tawil when it is completely surrounded by Egypt and Sudan? Both nations can block any land or air access. Or just arrest anyone planning to go there.
Also, if anything valuable is discovered or built there, Egypt and Sudan can settle their claims. Most likely is Egypt taking Halaib and Sudan have Bir Tawil, but could go the other way. Or Egypt could take both by force.
Could do something interesting, until Sudan or Egypt decide to kick everyone out (even if no one lays claim to it, they could still operate there under the guise of national security).
Bir Tawil and the Danube pockets are claimed, it's just that the border disputes mean that both parties argue it's the other side's claim; should the border dispute get resolved, there will be a clear owner of the land.