Maybe they shouldn’t bring D back to life… drop the name, make a clean break and come up with a new one.
OpenD is not that awesome.
It's hard to say whether I is available, or un-googleable.
J through W are also taken.
X++ is taken, but X seems to be available.
Y and Z are taken.
A would be an excellent choice were it not completely un-googleable.
Finally, B is a famous precursor to C.
APL is named after the book A Programming Language
which is extra clever because the "boot" button on early IBM mainframes was labelled IPL "initial program load".
Even better if it only worked with tuples.