Bloom Into You canonically has an aroace supporting character. However, FMC Yuu also reads as someone on the ace spectrum - I would wager demisexual. It’s not confirmed tho.

In "Cybernetic Tea Shop" the robot character is described as ace due to the lack of programming. She's not our only ace main though!

In “The Summer Hikaru Died” the author confirms that Hikaru has an aroace element to his character, and that reading the relationship between Hikaru and the other lead as queerplatonic is a valid interpretation.

I put it in this list however as comments suggest that this trait is less about individual variation, and more about what Hikaru is (an entity without primal desires). Please do correct me if this information is incorrect.