The first game that comes to mind is MysMe, I love all the characters in that game so much! Sometimes I even feel like downloading it and playing through the whole thing again! Another game I played recently where I liked everyone so much that I couldn't even pick a favorite is OverRequiemZ; I loved everything about it, including every single route. It actually surprised me that I enjoyed the "Dark" routes; I expected something typical of the yandere trope, but in my view, it went way beyond that—like seeing the characters' values twisted. It was really cool to see the other side of each character in that game! Then there's HanaKare; I can't pick just one favorite there either, whether it's among the love interests or the heroines!