Circle is [in Kanji, don't know]. Published 1996.
Duo and Wufei mostly shounen-ai with a little yaoi in the middle. There's even an equivalent of a songfic. There seems to be some angst piece between Duo and Wufei set to Bohemian Rhapsody (I kid you not). It seems to be some kind of anthology I think.
It's pretty hefty (98 pages). There are a few gags from the series like when Wufei was in a trance during the lack of air sequence and Duo keeps bugging him until he snaps out of it and starts kicking Duo's butt. Wufei wakes up and finds Duo in bed with him. He's not particularly happy about it. He wakes up Duo. Duo makes a pass and Wufei gives him a bobo!
Circle is Wakaidoumei. Published 1996.
First story is Quatre on earth talking to Dorothy about Trowa.
Second story which is probably an extension of the first story has minimal yaoi. Quatre is asleep and dreams that Trowa comes to his bedroom. They talk about Dorothy and Treize. Do some embracing and forgiving then next thing you know Trowa is getting to know Quatre up close and personal!
Circle is Over Network Unit-K. Published 1996.
Combines the first three Secret File djka. Trowa has a thing for Heero, but Heero is fascinated with Duo. After Trowa kissed Heero, when he was taking care of Heero in the self-destruct days, Heero is sad and torn (and crying). So Trowa leaves. While Trowa is infiltrating OZ, Heero and Duo are having a nice little time in the hospital where Heero left Duo during the series.
You see Trowa in OZ flying a suit and crying (thinking about Heero, no doubt). It kind of follows the series with its own twists. Not bad.
Circle is Hidalgo. Published 1995.
Well I call it shounen-ai rather than yaoi because the yaoi elements are so minor they are almost non-existent. Looks like Heero and Trowa at Antarctica. Trowa works on patching up Heero and they get horizontal with a big TO BE CONTINUED at the end.
There is also a story called Atonement where Heero is tied up and tortured by Treize. Treize is whipping him with a riding crop and cutting off Heero's clothes.
Circle is Haw Haw Bomber. Published 1996.
Lots of Chibi Trowas and chibi Wufeis in this little djka. The beginning few pages and ending few pages cover Trowa and Wufei after Wufei's defeat at the hands of Treize (i.e. campfire scene).
The rest has a strange little story of a chibified Trowa being horribly taunted by Duo and Quatre making little Trowa cry. He runs to Wufei for help. Wufei doesn't taunt him and he's instantly in love, Duo and Quatre do much sweatdropping here.