My memory’s more than a bit fuzzy since they were so long ago but I have two. I’ll try my best:
1. The first is a series from the 2000’s-2010’s though since I remember reading it at the public library it could also be from the 90’s or such. I just remember reading it at the time “spooky” kids lit was still popping off and A Series of Unfortunate Events was the big thing, that’s how I’m trying to place the time. It was about an Adams-esque family living in an old house and the children going on adventures and solving mysteries. I want to think it had supernatural elements like witches but I can’t be certain.
2. Even less remembered but still bugs me to this day. A young adult fantasy novel possibly published sometime after the 2000’s but before 2015 as I remember it being in my middle school library, I think it had a blue cover with I believe gold on it as well. But for some reason the spine I’m remembering doesn’t fit that description and is orange. It had a female main character and I think the plot involved slave trade and magic hair (?). I can’t recall what other sort of fantasy elements it contained as the one thing I do remember is I never got to finish it. It was in that sort of booming era of young adult fantasy series that Percy Jackson was part of, possibly on the tail end.