When most people think about anime characters with sex on the brain, they tend to think of male characters. While lewd anime dudes are definitely more common, there are plenty of lustful anime girls that always have men and boys on their minds.
Most anime girls who are boy crazy are focused on one or two specific boys. For example, Ayame Sarutobi of Gintama doesn't get particularly riled up about anyone except for Gintoki Sakata. Others have a broader appreciation for men as a whole - Bulma from Dragon Ball pretty much just wants a boyfriend and directs her energy toward multiple men throughout the series. Some characters, like Kagura Sohma of Fruits Basket, are focused more on romance, while others, like Panty of Panty & Stocking, are operating from a more carnal perspective.
Which of these anime ladies do you most appreciate?
Most of the time, Shizuka Marikawa is dedicated to her nonsexual roles. She begins as a school nurse, and eventually ends up managing the health and welfare of a group of students during a zombie outbreak. As the only adult in the group, she feels responsible for the kids in her care - but when she's drunk, her sexually forward nature takes over. She flirts with the students, and constantly thinks about all things sexy while blushing with embarrassment.
Anna Nishikinomiya represents an unusual variant of the boy-crazy trope. On the outside, she's a straight-laced student council president who has dedicated her life to wiping out all signs of perversion from society as a whole.
But underneath her prudish exterior beats the heart of a lustful maniac - Anna is so obsessed with Tanukichi Okuma that she becomes wild with passion every time she sees him, going so far as to forcibly feed him her "love nectar." Just goes to show how badly repression can warp a person.
Kurumu Kurono is a succubus, a species that is more or less defined by its lustful behavior. Toward the beginning of the series, she wants to make all of the boys at her school into her servants, but after her plan is foiled and she meets a boy she has true feelings for, her tune changes. Kurumu is still lustful, but all her lust is directed at Tsukune Aono.
Miia is a lamia, a species that's known for its intensely lustful behavior. Seriously, it's common practice for this species to kidnap human men in order to use them as their village's "communal husband" which involves a mass orgy in which the lamia try to get as many people pregnant as possible. This practice is now illegal since it typically involves assault, so the lamia need to send out representatives to human communities in the hopes of finding a man who will consent to come to the village.
Miia is an example of a lamia out in human society, and she's just as horny as the rest of her species - especially when it comes to her host Kurusu.