If you're looking for manga similar to Hayate the Combat Butler, you might like these titles. All recommendations are made by Anime-Planet users like you!
A+ student Ichinose Taiyo is the brains of his class. His grades are always high, he's generally liked by his classmates and everyone thinks he will get into a good college then onto a financially well-off career. But his life long dream that no one else, not even his family, knows about is to be a manga author, which realistically speaking has near impossible odds of working out. The reasons why he keeps it a secret is because he'd rather not try if he's more than likely to fail and also because he doesn’t want to end up like his classmate Anezaki Runa. Runa is also aspiring to be a manga author but is obsessed with it to the point where everyone keeps a distance from her because of her anti-social and weird habits. But one day, Runa finds out about Taiyo’s secret and forces him to pursue his dream. Taiyo learns that throughout his life, he has cared too much about public perception which will continue to limit his ability as a manga author unless he opens himself up even if it means rejection. With Runa’s help, he learns to believe in his dream and show his true potential.
Lotte, the princess of Ygvarland, hates men - a fact that ordinarily wouldn't be a problem given she's just a child. There's just one issue: the girl is a succubus that must suck the life seed from the male species or die! Now approaching adulthood, Lotte must learn to tolerate the opposite sex, but her royal highness won't have any of it. That is, until Judith, the girl's lady-in-waiting, brings Lotte a human boy to the demon world. This unfortunate young man, Naoya, must now open the princess's heart to his gender, but as caring and considerate as he may be, he'll certainly have his work cut out for him!
Lotte no Omocha resembles HnG, and is a good pick if you liked the latter.
They both have an innocent looking MC who is more than what he seems to be. There's the arrogant and childish little rich girl whom you will love to see her when she suddenly acts mature and responsible. And both Mangas have the MC working for said rich girl. Plus, both series have a lighthearted and comedic tone to them.
In order to pay for the debt that his parents left behind, Gin accepts an escort job from the bill collectors of the Tokugawa Group conglomerate. The client is a girl named Hikari who goes to Tokugawa Private Academy. Using the experience he gained from his previous part-time jobs, Gin protects Hikari along with the other escorts, Suke and Kaku. However, Hikari seems to have a hidden secret...!?
The two mangas are pretty much the same, with Yellow Gate being the more adult. Both have the same premise of boy accepting job due to massive debt and his new, super rich, boss beingf in love with him.
Again, Yellow Gate has more ecchi (getting quite extreme) and Hayate is generally funnier with more parodies, not that Yellow gate doesn't have any.
In short, basically the same series, fans of one will probably like the other.