=ARRAYFORMULA(UNIQUE(QUERY(LET(raw_matches,FLATTEN(IFERROR(REGEXEXTRACT(SPLIT(REGEXREPLACE(B:B,"(youtube\.com/watch\?v=[A-Za-z0-9_-]{11}|youtu\.be/[A-Za-z0-9_-]{11})","|$1|"),"|"),"youtube\.com/watch\?v=[A-Za-z0-9_-]{11}|youtu\.be/[A-Za-z0-9_-]{11}"))),IF(ISBLANK(raw_matches),,"https://"&raw_matches)),"where Col1 is not null")))