duniazade prompted me with Snape, Luna, and Hermione (wildcard genre): Chizpurfle eggs, Lute of Celestial Gnomes, and the Morose Coachman.
A Not-So-Secret Love Sign (PG; Severus, Luna, and Hermione; 300 words): Attention to detail is a hallmark of love.
"—concludes our programme. Tune in Christmas Day to play along with the further musical adventures of the Gnomes of Celestia!"
Frowning, Severus turned off the Wireless; to his relief, Hermione shifted in her sleep but did not wake as he slipped out of her room.
His eyes widening at the familiar sound, Severus rushed downstairs and into the kitchen. "A Lute of Celestial Gnomes!" he cried, seizing the half-wrapped, pink and sparkling instrument from his wife's hands. "Look at the golden strings!" He turned it upside down. "And see here? This is the Secret Love Sign of the Celestial Gnome Queen on its base! It's real!"
Luna giggled. "Of course it's real, you Gnomie."
Clutching the lute to his chest, Severus said, "Knowing the hallmark of the most desired toy of the season does not make me a Gnomie."
"No, I think listening to all the broadcasts made you one. In any case, you weren't the only father who promised his daughter a lute without having one in hand. There were loads of dads vying for Malna's stolen lutes at the Morose Coachman. Unfortunately, they brought Galleons. I brought hag's caviar."
"Chizpurfle eggs?" asked Severus.
"Your last crock of them, actually, but they're not nearly as rare as the lutes. Even Malna was keeping one back for herself."
"Sod my eggs!" Severus exclaimed. "She wants it to lure children!"
"Don't worry. It was Harry who thought a hag might have stolen the toys from Wheezes because George told him he'd seen Malna hanging 'round the shop. She's in custody."
"Good," Severus said, flushing as Luna touched the hand with which he was stroking the lute's frame. "I was just making sure it was smooth. We wouldn't want Hermione getting a splinter."
"Of course we wouldn't," Luna replied, "Gnomie."
swissmarg prompted me with Hermione, Severus, and Mrs Zabini (wildcard genre): fire slug slime, Endless Ointment of Magic, and the Staff and Wand.
Burning Passion (PG; Hermione, Severus, implied others; 100 words): Auror Granger follows a lead.
The Staff and Wand was an establishment for wizards seeking the company of wizards, which made it difficult for Hermione to seek answers there. Fortunately, Snape owed her a favour.
"What took you so long?"
Snape handed her a phial. "You're welcome."
"Is it evidence?"
"It's a processed form of fire slug slime, and Newt Scamander agrees with your theory that it could have been mixed with Endless Ointment of Magic to produce the unfortunate effect."
"Turning a poor man to ash isn't an 'unfortunate effect'. It's murder."
"Agreed, and for Mrs Zabini, it's a rather efficient method of divorce."