ScoreRank
Not sure on the future of this, but given it is used in the save-failed-reply pull request (#18785) I think it's fine to add back for now. Without this, JSON parsing of older scores in server-side storage will fail on missing enum type.
BeatmapSetInfo
BeatmapInfo
SeasonalBackgroundChanged
osu://
RealmNamedFileUsage
GetBeatmapSetRequest
LocalisationManager