Not one, but two!

As is evident from the nature of the exchange, both of these fics have AU settings.

For Truth, For Duty, and for Loyalty (Richard III) by gileonnen - Richard of Gloucester has a plan for the planet of Albia, and Ratcliffe wants to be part of it. Science fiction AU. Featuring art by speak_me_fair.

Delirien (1 Henry VI) by lareinenoire - In the giddy years of the early twentieth century, the families of York and Lancaster seem to have come to an uneasy truce when Humphrey Lancaster befriends young Richard York and offers him a chance to mend his wrecked fortunes. What neither of them anticipates is the war that will destroy everything they know. Featuring a fanmix by cherith and art by gileonnen.

Both links are to the index pages, which include information about the artists as well.