The Missing Internet Adventures (usually just MIAs) are a series of largely largely stand-alone stories chronicling the adventures of previous incarnation of the Doctor — essentially the ones not currently occupying the centre stage of the IAs at the time the writing on the story begins. As a rule, they have tended to be less challenging than some of the plots appearing in the IAs.
The Doctor Edit
Classic Doctors Edit
Cascade, the first MIA, appeared in June 1996 fresh on the heals of the just completed DeathRace. Since then the MIAs have for 24 stories focused exclusively on the 1st seven incarnations of the Doctor, apart from a brief appearance of the 8th Doctor in the multi-doc adventure The Exiled Ones. While they've lacked the same ongoing-narrative that defined the life of the 8th Doctor, the MIAs have allowed writers to indulge in expanding the known adventures of these 7 Doctors and their companions, exploring lost continuity and new ideas.
8th Doctor Edit
Neither truly Classic nor of the New Series, the 8th Doctor's adventures in print came to an abrupt end with the unveiling of both versions of the 9th Doctor — Richard E. Grant and Christopher Eccleston. But where the novels and the DWM comic wrapped things up and simply left the door open to further exciting tales, the narrative unfolding in the IAs at the time was left incomplete. Since then, there have been no MIAs focusing on the 8th Doctor either as a continuation of the ongoing narrative or the explore adventures previously unseen.
9th Doctors Edit
Despite the sole 10th Doctor IA — The Memory Game — currently being in a multi-year hiatus, April 2010 saw signups for TDIA #01, what was intended to the first of a loose trilogy of stories set somewhere during the "gap year" occupied by the various 2009 specials. The other two stories never eventuated.
11th Doctor Edit
There are not 11th Doctor MIAs.
The Renegade / War Doctor Edit
There are currently no IAs featuring the this incarnation as portrayed by John Hurt.