- near-stock
    - without google
        -  AOSP
            - CAF -> altered AOSP by Qualcomm to optimize it for their cpu. Usually when Google starts working on a new Android version, they'll fork from CAF at the beginning. Very often Google will be adding "new" features specific to the new Android version, while Qualcomm will continue with performance enhancements and bugfixes against the "old" baseline. So when a new Android revision comes out, you have two baselines: CAF which is usually "ahead" in performance but "behind" in features and has more bugs, while AOSP is “behind” in performance (relatively) but “ahead” in features.
        - LineageOS
        - GrapheneOS
    - with google
        - Pixel Experience -> Pixels. Offers an ASOP and a CAF version. Has less bugs than AOSP / CAF and has a few added features
        - Android One -> made by Google for other manufacturers
        - Android Go -> made by Google for other manufacturers (lower-end phones)
- heavy  skinned
    - without google
        - MIUI -> Xiaomi
        - EMUI -> Huawei
    - with google
        - One UI -> Samsung
        - OxygenOS -> OnePlus