After the large discussion about .io being delegated as a gccTLD by google[1], and the subsequent purchase of every single two letter (as in, a-z) .io domain[2], I figured I would put together a list of all free two character .io domains of the form f4.io. The linked list contains all free domains of the form [a-z][0-9].io (as of posting, of course). Enjoy.
Sure thing! I ended up picking up a few fun .io domains, so I figured I would give back to the hn community. After how quickly the a-z two letter domains disappeared, I was surprised to see that the majority of letter + number domains were still available. Enjoy t0.io.
Also, for those wondering, not all registrars accept two character .io registrations. Of those who do accept such registrations, the cheapest I've found is gandi at $40/year.