Yuru Camp was my favorite by far. Comfy as fuck, beautiful nature and interiors, cute girls, a god tier OST, and of course, the mark of any good show, gratuitous cooking and eating scenes. Maybe it's just me but I felt like there was a bit of a theme with Shimarin's character development, that you should step out of your comfort zone as an introvert but you don't have to completely change yourself, it's ok to keep enjoying things alone. Not sure if I was imagining it but it resonated with me. My only regret is that I didn't watch it while it was airing.
Second is probably Jashin-chan Dropkick for being stupid fun that didn't take the lazy way out and completely copy the manga panel for panel like most adaptations of comedy manga.
Zombie Land Saga was pretty good too, never thought I'd enjoy an idol show but I liked all the girls > designs and the producer was hilarious. The rap battle in episode 2 might be one of my favorite surprise moments in anime.
High Score Girl may have been mediocre CGI but it was honestly a pretty good adaptation that did a better job of playing up the feeling of childhood romance than the manga imo. I never got around to finishing Hataraku Saibou but it was really interesting and creative. Other than those, I don't really remember much of anything else from 2018, except Goblin Slayer for being a disappointing adaptation.