I 'm the owner of a pretty good doujinshi collection, and I've got using a very selective way.
My Slayers doujin collection is shorter and varied than the "Dragon Ball" ones. I've got many of them accidentally, and I have no favorite, I like any of them better than others, thought.
 
  スレイヤーズ 同人誌, 巻代様発行
COVER DESCRIPTION OPINION
A doujinshi series focused on every main character and I was lucky because I got all them at once. Short stories by different authors
*KD-Garnet*

Varios

20p/A5

***
*KD-Lapislazuli*

Varios

20p/A5

***
*KD-Peridot*

Varios

20p/A5

***
*KD-Indicolite*

Varios

20p/A5

***
*KD-Hematit*

Varios

20p/A5

***
     
*Lovely Place*

Tomo no Aki

28-26p/A5

****
This book is quite rare. On first place, it's by Tomo no Aki, although it also has pin-ups for other authors, even Woodyland. several stories about the relationship of ZA and Alfred, or just Alfred.
     
*Hamapu*

Raimaru aka  MIX SALAD ALPHA

28-26p/B5

**

Doujnshi collection I got thanks to my friend Leviosa ini Japan. The most notorious thing about these books is the art tries to imitate Araizumi's, thus they have an interesting lineart and coloring. Short and gag stories about the main characters turned into cats.
     
*(?)*

Subaru Y

26p/A5

***
A doujinshi that I got thanks to my friend Leviosa8 in Japan. Short stories about their relationship.
     
  *Wyafarer*

Undertaker

34p/B5

***
Quite rare book by Udertaker, best known as "Morisaki" in the net. It also has pin-ups by other authors. Short and gag stories..
     
  *Hamapu*

Chiharu Kurase

50p/B5

**
Pretty beautiful cover for a book which happens to be a novel (fanfic) only. It also has illustrations about Amelia and Zel in human form.
     
  *Hayashi*

Quo Vadis

16p/B5

***
A pretty rare book focused on Amelia and Sherra. In fact I own that one because of that. One story is about Sherra and Gaarv, the others about Amelia and his cousing.
     
The almost complete colectión by "Black Panda" cicle. There is another title, "Sutyarika" (mostly 4Komas) that I got by exchanging doujin scans. They're half short stories by two different authors and focused on L/G & Z/A. The book "Sleeping Party" isn't the original, which has a blue cover, and it also has two less pages. Besides, I've two versions of "Fortune", which the only difference is the covers and papper quality.
*Fortune Doctrine*

Black Panda

28-26p/B5

****
*Summer Party*
 
 Black Panda
 
 32p/B5
 
 ****
*Fortune Do Corine*
 
 Black Panda
 
 28-26p/B5
 
 ****
*Spring Party*

Black Panda

28-26p/B5

****
     
*Berserker 1&2*

Quo Vadis

28-26p/B5

***
I got the two books in a single pack on Ebay. The title makes reference to the true nature of Zel, but the books are about many things about his life, mostly gag stories, so all the Slayers gang, even Rezo, appear on those books. The bad thing is they're 4-Komas style, mostly.
     
*Zelgadiss Only Book*

RSF, NOL&BAGUR


****
Aaah! too bad it's only the second book, because certainly it's a rare and odd piece. In this story, Zel is cheated by some mazoku, and later, Xelloss also joins the party. So Zelgadiss has to fight against them. Is interesting to notice all "Dragon Ball" references on this book, and the author is Earthrock, a friend of QP/Diana.
     
*Zelgadiss Only Book*

RSF, NOL&BAGUR


****
This is a forgotten book. The art is nice and it has some interesting pinn-ups. It has some short and gag stories, and some long and serious ones. The problem is this book would be more interesting if I could understand them.
     
*Glamorous Cage*

Tomo No Aki

62p-B5

*****
This is a recompilation book, an anthological. Here, you can see some popular doujin, like "Pink Loves Him This book has some hentai humor-stories, and some regular stories made by/for girls. The art is really good and full focused on Z/A.
     
*Voice*

Tuberculin Tsuji
26p-B6

****
This book is well-known among ZA fans. I'm not sure, but I think its circle also makes "D.Ball" doujinshi. Indeed, this book are several gag stories about ZA, and the art is correct.
     
*Next&Try Justice*

Pelican Group

36p-B5

***
Another book which you can find often in the net. It's short and gag stories related with Next&Try's events; the art is comical but it would be better if we would be able of understand the gags.
     
*?*

URA 24

62p-B5

*****
I don't know the real title, "URA-24" is the author's nick name, a popular artist among the Japanese fandom. The art is fine, but I know URA's art, and It could be better. The story is focused on Amelia's declaration, and Zel's despise, among short and gag stories. It's beautiful, but It isn't original.
     
*First Love*

WoodyLand/Tuberculin/Fijiya&Others

78p-B5

****
I have been looking for this book so long. It's a big book by several authors, and among them, there is "WoodyLand" (Of course!). The stories are focused on Z/A relationship in romantic way. Those are good, but the disturbing thing is the big difference between every author of the book.
     
*Tempint3*

Halopack

78p-B5

****
This one is well-known among ZA hentai fans. It's from Halopack' series and it might be one of its first books since the art isn't as good as other books. The story is long: Lina and Amelia have a hard discussion which makes Amelia very angry; later she still arguing with Zel, who gets tired of that and cut off the stuff radically. Finally, he gets Amelia changes her opinion.
     
*Z&A Only Book*

Mannen Boss/TOYOTA SAORI & CHIMO UZURA

30p-B5

***
This book is coupled with another one about L&G. In fact, it's two short stories focused on Z&A, in separated ways. Anyway, the covers is beautiful.
     
  Two books of certain series of 5 books; the last one is "Yami No Sortilege" which you could find at "Dark Roses" website. It's a story about Xellos, his Lord, Fibrizo and the rest of Dark Lords crew, main characters don't appear in the thhird book, althought the second book os more focused on Z/A. It's noticeable the evolution of the art since the first book to the last. In "Idol", Zellas is a male
*Honoo No Sortilegie*

Monado

78p-B5

*****
"? no Sortilege"
Monado

42p-B5

*****
*Idol*

Monado

78p-B5

***
 
     
*Making Love*

WoodyLand&Tomo No-Aki

78p-B5

*****
The title is very descriptive. This book is a collection of 5 hentai stories with plot. The first ones are by "Tomo" circle, and the rest by "WoodyLand", including an illustrated novel. They're humoristic, serious and descriptive; and my fav is the later one. Plus, I like it because the hentai scenes doesn't show Zel's hip, only.

 

     
*Zenbu Dakishimete*

Fujiya

30p-B5

****
Another ZA book. I got it in Doujin-Box because nobody wanted it ^^ At first, I was scared because it might be a "bad" doujin (novels and stuff) but in the end, it's several stories by different authors; the main one is about Later Next's Events.
     
*Giken Muyou!*

Ikasama-Koubou

34p-B5

***
Short, gag and semi-romantic stories about all Slayers characters are gathered in this book. there are several interesting illustrations, too. I also got this from Japan thanks to Laura
     
*Revenge*

(Unknown Author)

26p-B5

**
The most interesting thing about this book is its looks: Black pages and white text, even silver. Short stories about Vargaarv
     
*Slayers-5*

K.Shima

60p-B6

***
A doujin which has a odd art focusing on Mazoku; it's tragicomic stories about them. All characters appear here, even Lei Magnus.
     
*(?)*

Yura Fukami, Kaze No Ohkoku, Lawg y Mion Tsukioka

26p-B5

****
This one is from Ebay. It's several short Z/A stories by different authors, but there are several cameos of other characters. The main plot is one of those authors is the webmaster of the "official" Z/A fanclub website, I think.
     
*Bokunioritekatenshi*

Fijiya
38p-B5

****
I got this one in Doujin-Box, and it's quite popular among hentai books. In fact, it's four stories about Z/A (The last one is a novel, though) in shoujo style, the art is sweet and romantic, and the hentai story would be "for girls" A god book for Z/A fans
     
*Splastic Comedy-2*

O-jiro

26p-B5

***
Another book which I got because Laura gave me it. This is by O-jiro, a very popular circle because its L/G stories and sweet art. The plot is interesting: all Slayers characters get zapped into childhood. The worst thing is greater part of the book are "free talks", and it's to fail of taking advantage of the book
     
*Anthology-1*

Several Authors

90p-B5

****
I got this big book from Laura, when she come back from Japan^^ It's an anthology by several authors, therefore it's a stories mix. I liker serious stories about  Xelloss or Vargaarv, as well as its odd art,
     
*Trouble x Haven*

WoodyLand

24p-b5

****
This book is a birthday present and it's made one of my fav Slayers doujin circles. It's a chaotic and gag Slayers story with some Zel torture and ZA hints. Very funny and well-drawn
     
*Destinity Half*

WoodyLand

20p-B5

*****
 
This doujin isn't original, but a remake edition building with laser photocopies and put for sale like an original book. I don't if it's original or not, but the author is my favorite ZA doujin circle, "WoodyLand". A Z&A story with light soft-core
     
*Love destroyer*

Shi-sin-De

44p-B5

****
Shi sin De is one of the most popular Slayers doujin circles. Because of that, and because I've been seing this doujin in whatever place, I made my mind to get it from Ebay
     
I got the first book thanks to my friend Raquel (hugs!) who got it in E-Bay. I wanted it since I saw it on Aino-Anime, and it's a long story focusing on Zelgadiss compared with a cactus. The second book is from Ebay, and it's basically a continuation of the first one.
*Sahoten-1*

26p-B5

***
*Sahoten-2*

22p-B5

***
     
*Reminiscence of the Past*

Black Eyes

38p-B5

***
I got this doujin in my last birthday and I liker it than "Take your Courage!" The most amazing thing of this doujin is it has a story which 's just like Helena's "Kodomo no Slayers"!
     
*Tyni*

50p-B5

J. Sairo

***
 
I got this doujin from the Spanish shop, too. It's by a very popular Slayers hentai author, I think. Certaly its stories are funny... if you like hentai. I don't mind it so much, but I laughed a lot with it.
     
*Take your Corage*

Purple Company

32p-B5
**
 
A usual Slayers doujin I got from the single Spanish shop which has Doujin for sale. I got from postmail and I don't like it so much. I has any funny stories but that's all.
     
*Konoyo Ha Watashi No Tameni Aru*

Jolly House

22p-B5

**
This doujin was a birthday present from any years ago. It is nothing special, just a funny story of first movie