I looked for a minute for this. Yeah there's not a ton of DDLC preg art, but suppose the year was 2015 and the game came out in 2009? There'd be almost none, if a single piece.
I feel blessed honestly with how much more preg smut there is on the web in recent years. There can always be more, especially for more niche games/copyrights, but it's certainly better than it ever was before.