Sure, Watchmen is aimed at adults. It has sophisticated storylines, challenging concepts, and imagery that demands a certain level of maturity and understanding from the reader.
Generally speaking, the Deadpool comic is considered adults only. It features a lot of intense action, dark themes, and irreverent language that may not be suitable for younger readers.
There's also 'Blue is the Warmest Color' which has been adapted into a comic and then a movie. It doesn't solely focus on bisexuality but has elements that can be relevant. It's a story about love and self - discovery that young adults might find interesting and thought - provoking, and it can start conversations about different sexual orientations.
Adults can get free comic books on rare occasions. Maybe through giveaways by comic book companies on their websites or as part of community outreach programs. But you have to keep an eye out for such opportunities.