BEJ48's Trainee (预备生 (Yùbèi Shēng), Kenkyuusei or Research Students). They currently have 3 members, although 1 has announced graduation.
Chen YiFei (菲菲 FeiFei) - 1st Generation (Team B)
Wu YueLi (蛋蛋 DanDan) - 1st Generation (Team B)
Li Na (牙妹 YaMei) - 1st Generation (Team E)
Yang YiFan (木易 MuYi) - 1st Generation (Team E)
Chen YaYu (多肉 DuoRou) - 1st Generation (Team J)
Fang Lei (房总 FangZong, 蕾宝 LeiBao) - 1st Generation (Team J)
Ge SiQi (葛格 Gege 鲜鲜, XianXian) - 1st Generation (Team J)
Huang EnRu (Ruru) - 1st Generation (Team J)
Li HongYao (蛟娇 JiaoJiao, 焦糖 JiaoTang) - 1st Generation (Team J)
Liu Xian (雪饼 XueBing) - 1st Generation (Team J)
Ren XinYi (柚柚 YouYou, 怡夏子 YiXiaZi) - 1st Generation (Team J)
Ren YueLin (好好 HaoHao, 教主 JiaoZhu, 未来 WeiLai) - 1st Generation (Team J)
Shan XiWen (茜茜 QianQIan) - 1st Generation (Team J)
Shi YuSha (暖暖 NuanNuan, 奶茶 NaiCha) - 1st Generation (Team J)
Sun YuShan (Yokie) - 1st Generation (Team J)
Wang YuXuan (芋圆 YuYuan) - 1st Generation (Team J)
Ye MiaoMiao (喵喵 MiaoMiao) - 1st Generation (Team J)
Yang Ye (社长 Sezhang, 二毛 ErMao) - 1st Generation (Team J)
Zhang HuaiJin (锦鲤 JinLi) - 1st Generation (Team J)
Zhang HanZiMo (Yukari) - 1st Generation (Team J)
Xu WanYu (猫丸儿 MaoWanEr, 小猪肉 XiaoZhuRou) - 1st Generation (Team J)
Hu LiZhi (梨汁 LiZhi, 瑶瑶 YaoYao) - 2nd Generation (Team B)
Li MuYao (木子 MuZi) - 2nd Generation (Team B)
Liu ChongTian (恬恬 TianTian, Tina酱 TinaJiang) - 2nd Generation (Team B)
Mao QiYu (猫吃鱼 MaoChiYu, 猫仔 MaoZi) - 2nd Generation (Team B)
Sun XiaoYan (小眼 Xiao Yan, 小幸运 XiaoXingYu) - 2nd Generation (Team B)
Zheng YiLing (10) - 2nd Generation (Team B)
Huang ZiXuan (39) - 2nd Generation (Team E)
Li Ye (火华宝 HuoHuaBao, 小叶子 XiaoYeZi, 小草莓 XiaoCaoMei) - 2nd Generation (Team E)
Xu Jing (小青蛙 XiaoQingWa) - 2nd Generation (Team E)
Zhao DiEr (笛儿 DiEr, Dear) - 2nd Generation (Team E)
Jin LuoSai (赛赛 SaiSai, 小田螺 XiaoTianLuo, 小金猪 XiaoJinZhu) - 2nd Generation (Team J)
Lan Hao (阿兰 Alan) - 2nd Generation (Team J)
Liu YiFei (一一 YiYi) - 2nd Generation (Team J)
Qiao YuKe (乔儿 QiaoEr, 小可乐 XiaoKeLe) - 2nd Generation (Team J)
Zheng XinYu (小雨毛 XiaoYuMao, 心雨 XinYu) - 2nd Generation (Team J)
Shen XiaoAi (兔子 TuZi, 大爱 DaAi) - 2nd Generation (Team B)
Qu MeiLin (酥酥 SuSu, Q酱 QJiang) - 4th Generation (Team B)
Gao WeiRan (艾丽 AiLi, 艾琳娜 AiLinNa) - 4th Generation (Team E)
Peng JiaMin (彭彭 PengPeng) - 4th Generation (Team E)
Xiong Xin (Au, 三斤 SanJin) - 4th Generation (Team E)
Zhang DanDan (Dan) - 4th Generation (Team E)
Lou Shu (OO) - 4th Generation (Team J)
Zhou Xiang (香菜 XIangCai) - 4th Generation (Team J)
Cheng YuLu (小璐 XiaoLu, 咕噜 GuLu) - 5th Generation (Team E)
Li LiMan (小满 XiaoMan) - 5th Generation (Team E)
Ren ManLin (麦芽 MaiYa) - 5th Generation (Team E)
Wang DanNi (丹妮 DanNi, 丹丹 DanDan) - 7th Generation (BEJ48 New Formation)
Zhang RuiYi (Jasmin, 小宝 XiaoBao) - 7th Generation (BEJ48 New Formation)
Bao Ying (年糕 NianGao) - 15th Generation (Team B)
Jin WanYing (鲸鱼 JingYu) - 15th Generation (Team B)
Wang JiaQi (三三 Sansan) - 15th Generation (Team B)
Ma MingXuan (冰灵 BingLing) - 15th Generation (Team E)
Wang SuNan (南南子 NanNanZi) - 15th Generation (Team E)
Zhu YueTong (汤圆 TangYuan) - 15th Generation (Team E)
Shan ZiHan (念念 NianNian) - 15th Generation (Team B)
Guo YiChen (郭郭 GuoGuo) - 15th Generation (Team E)
Li QingYu (金克丝 JinKeSi) - 4th Generation (IDOLS Ft) (2019)
Yang YuXin (馨宝 XinBao) - 4th Generation (IDOLS Ft) (2019)
Li HaiLin (李李 LiLi, 梨子 LiZi) - 6th Generation (IDOLS Ft) (2019)
Zhang YuQian (阿倩 AhQian, 倩妹儿 QianMeiEr) - 6th Generation (IDOLS Ft) (2019)
Xiong YiYi (蔸蔸 DouDou) - 6th Generation (IDOLS Ft) (2019)
Fu YiXuan (Fufu) - 4th Generation (2019)Stages