Almost all anime I really like are super stereotypical comfy anime, picking one is very difficult. The most underrated is Hidamari Sketch in my opinion. ARIA is also extremely strong. Non Non Biyori is a classic. For a lesser known one I put forward Tanaka wa Itsumo Kedaruge. Apart from that most good CGDCT anime have a strong Iyashikei component to them are very comfy. Classics are Lucky Star, K-ON!, Azumanga Daioh and Ichigo Mashimaro. For more modern takes on this type of anime the newer Kirara anime such as Kiniro Mozaiku, Gochuumon wa Usagi desuka and Yuyushiki are popular under "comfy bros".