There's also Air, by the same original writing team as Clannad and Angel Beats. Although I highly recommend the movie version of Air rather than the TV version for the best overall experience. The TV version is a condensed version of a visual novel, and there's just this really confusing plot twist in the middle that they don't properly explain. The movie version just does away with most of the extraneous stuff and does a really good job of presenting the core story, as its own thing. However see the TV version as well. Don't forget to see the Air in Summer OVA, and you're supposed to watch that after seeing episode 8 of the Air TV show. The Air TV show is still worth seeing after seeing the movie, as the entire thing just has many more layers to the story than the movie, so they're effectively different things.
Also, ef: A Tale of Memories and ef: A Tale of Melodies. Which are also visual novel adaptations. For these however, one plot "spoiler" helps make sense of the plot, because it's just not explained at all in the anime, I guess they assumed the viewer was already familiar with the source material. There are actually two "sister cities" in this series, with buildings that are replicas of the buildings in the other city. This is especially noticeable in relation to the church in the series. One set of characters go to the church and this guy is always there, and the other set of characters go to the church and this girl is always there. It's actually the two churches in the different cities, which explains why the guy and the girl never run into each other. The guy and the girl have a connection that's explained in the second season.