Everyone loves a good butler character, and a boys love butler character is even better! Here are some visual novels featuring them. 

Itsuwari no Alkanet, or False Alkanet, was a Japanese-only mobile game released by NITRO CHiRAL – under the name CHiRAL MOBiLE – and Digiturbo, from 2010 to 2012. The game was set among a wealthy family in Taisho-era Japan. One of the main characters in the game was Kurae Kazuki, a butler who pledged himself to loyally serve the family throughout his life.

He also appeared on the tie-in Drama CD, where he breaks from his serious, dramatic role in the main story to worry about the dinner menu for the evening.

 
2011's Hadaka Shitsuji, released in English as Hadaka Shitsuji - Naked Butlers, is an all-butler extravaganza in which you play a young man hired to be the interim "master" to a large household's worth of butlers while their employers are away. The protagonist is very sadistic in his treatment of the butlers, who offer a variety of BL character types. 

2017's Tsumi naru Rasen no Ori -Whispers of Iscariot- has not been translated into English. The 19th century western setting is the backdrop to a tumultuous love triangle, one third of which is made up of Glenn Managarm, the household's butler. 

2017's Eden-ui Neomeo, or Beyond Eden, is a Korean Boys Love visual novel set during the Victorian era, and centres around Alex Wake, a young man seeking revenge against the wealthy Edenic family. The family's butler, Theodore, has a repressed attraction to Alex that Alex uses in order to manipulate through sexual coercion.

Chess of Blades, also from 2017, is an English-language visual novel that was funded via Kickstarter. Unfortunately, the stretch goal for butler Silas to have a route was not reached during the campaign, and he is present as a non-sexual supporting character only.