The Republic of Heaven:
A photoshop of Amarisa and Raniel here, by 
caoilin_noir
Two collections of sketches, one of Amarisa and the other of Raniel, by songgoeson, also a sketch of John and Amarisa sleeping, and one of Raniel and Sherlock with Raniel curling up on the pillow.
A Christmas drawing and an illustration of a scene from Part Four, by eksdan
By birddi : a title page, as well as pictures of Sherlock and Raniel, John and Amarisa, and Raniel and Amarisa
A drawing of Amarisa by lightflooby
A wallpaper of all four main characters by anuminis
Sherlock and Raniel and John and Amarisa, both oil on canvas by artconserv
An illustration from Part Eight, of John and Amarisa at the pool, by xxxxxx_6x
A rough sketch of all four main characters, by sognagil
Another photoshop of Amarisa and Raniel, by yasei_raiden
Reaction:
A title page as well as a spacer, by birddi
Gravid:
A poster, by basingstoke
A drawing of Sherlock and Joan by ike on mtslash
A title page and comic by birddi
Semper Fidelis:
A poster and title page by mabivia onefoolsfollywas also inspired to make a gif of John in 'the-fuzzy-cable-knit-sweater-of-noth
A cover page by moonblossom
Deceiving Appearances:
A title page by birddi
John and Amarisa. I love how you describe John and Amarisa sleeping close together, even though there's really no room for them both in bed, so this is kind of inspired by that :)
Sherlock and Raniel. Pretty sketchy-- Cumber!Holmes is tough to draw. The scene of Sherlock and Raniel talking in bed stuck in my mind, so this is a bit like that, with them trying to be a bit more affectionate with each other.
Okay, now I have no excuse and should get back to work...