There are a few different lines of dolls currently sold through AG. Historical aka Beforever, Girl of the Year, My American Girl AKA JLY, Bitty Twin, and Bitty Baby. Historicals are available sometimes for many years predictability of retirement of these comes and goes. There will be more there is rumored a 50's doll coming and AG has hinted at a new African American Historical (Civil rights would be cool?) Last year they archived four historicals Marie Grace, Cecile, Ivy, and Ruthie. The Year before it was Molly and Emily. They recently launched the new Beforever line complete with all new outfits and Samantha brought out of archives. We don't know when and if AG will bring another out of archives. When they want to archive a doll it works like Girl of the Year.. they are available until they sell out or December 31st usually. This year Marie-Grace and Isabelle are kinda lagging. I believe both dolls are now officially sold out at least online.
Girl of the Year is released once a year and they are archived when they sell out or December 31st. Girl of the Year is based on current times and often the characters have challenges they have to over come.. Isabelle was kinda bullied, she didn't feel good enough, she felt like she was in her sisters shadow, Saige had her program cut at school and grandmother was sick, McKenna had a learning disability.
JLY line is basically a design yourself line but it can't be too customized AG wants your child or yourself to pick out your favorite doll from that line or one that looks closest to you or your daughter and you can make her whatever you desire (Skater, Skier, braces, geek, fashionista) and basically tell your own story. There is a retired set of blank books to write your own story. The JLY, Historical-Beforever, and GOTY are all 18 inches tall and can mostly share clothes.
Bitty Twins are babies (Toddlers) with hair and you can buy them separate or together. Bitty Babies have kinda painted on peach fuzz and both of those lines are 15 inches but sometimes can share clothes with the 18 inches too!
American Girl used to make Angelina Ballerina items and a collectors doll line called Girls of many lands.