From Sakura-Crisis:

One day, as Suzuri was walking past a river, she suddenly saw a HUGE peach slowly flowing! Due to the fact she has not eaten since the start of her journey, she decided to just conclude the huge peach was a god sent and did the most logical thing anyone would have done - eat it. However, just as she had her first bite, a young male jumps out of the peach! And before Suzuri knows it, she’s the 18th master to Momo who could do anything that Suzuri commands! What kind of danger would they encounter on their journey as they face a god that goes by the name Kyuui? And what dark secret does Momo have?!

[From DMP]:
The Hybrid Child is an amazing android that can grow if it is lavished with enough love and care from its owner. Neither fully machine nor fully human, the various Hybrid Child models develop strong emotional bonds with their owners. This volume contains several short stories of love, sacrifice, and drama: Young Kotaro learns the importance of responsibility when his Hybrid Child's lifespan runs out. The tragic swordsman Seya learns to love again with the help of his Hybrid child, Yuzu. The final tale tells the story of Kuroda, the creator of the Hybrid Child designs, and how his lost love inspired their creation.

[From Mochi*Mochi]:

----I said that I wouldn't accept anything else but Hazuki--- Kotarou found Hazuki at the trash dump one day and took him into his home. It turned out that Hazuki was a Hybrid Child, a doll that grew and developed in response to its owner's love and attention. Experience Nakamura-sensei's stories of earnest, pure love in this three-part series, including a never-before published short and extra!!

The young pirate head Sakaki met the autistic but beautiful samurai Murou...
Why did Murou have the other half of the treasure island map left by Sakaki's grandfather? Why did Murou keep to himself? Could Sakaki open Murou's closed heart? And how should he handle his best friend who loved him, Juurou?

After a scandal got him kicked out of his position at court, Takaaki's been idling the days away at his manor, impulsive and bored. Then one day his friend Naruhito stops by and tells him an insane story about the most beautiful woman alive—and drags him off in his attempt to win her heart. Tagging along, Takaaki soon realizes that the "Princess" isn't exactly who she (he!?) seems to be. Who exactly is Princess Kaguya, and what is the dark secret behind her (his!?) past?
(Source: Storm in Heaven)

Popular for Junjou Romantica, Shungiku's earlier works were more samurai romance/yaoi of this sort. Here we have a basic spoiled brat and his bodyguard developing feelings for one another.
(Source: MangaUpdates)

Isaka is secretly in love with his caretaker and former childhood friend Asahina. However, Asahina is obsessed with Isaka's father... or so it seems.

Sekaiichi Hatsukoi ~Onodera Ritsu no Baai~
Onodera Ritsu has just transferred from his father's publishing company to Marukawa Shoten. Assigned to the shoujo manga division, he crosses path with the person he'd least expected to meet. Takano Masamune is the editor-in-chief of the division Ritsu's been assigned to, and the two seem get off on the wrong foot right from the very start when Takano unexpectedly kisses him. However, there is more to than what meets the eye: Takano is actually Saga, Ritsu's senpai and high school love-- whom Ritsu had thought to have played him for a fool by taking his affections for granted when he confessed and summarily dumped him. (from zero_kiryuu)
loosely connected to Junjou Romantica (Usami Akihiko's name's in here!)

Sekaiichi Hatsukoi ~Kisa Shouta no Baai~

The second story tells about Ritsu's colleague Kisa Shouta
who works with him at Marukawa Shoten's Emerald shoujo
manga department and ever smiling, suave and irresistably handsome Kou Yukina.

The rumor goes that sometimes, late at night, a white monster appears, and if you should look upon it you'll be devoured. One night, Tetsu happens to glimpse the man behind the monster, and decides that the man would be the one to teach him the sword and allow him to take his revenge. However, the swordmaster Shino is hardly interested in taking on any students. What will Tetsu have to do to get his revenge, and what happened to Shino in the past to turn him into who he is...?
Includes: Castilla