Rack of Lambda

Personally, I don't think a new function is warranted for the delimited values example, as you can simply combine UNPIVOT with TEXTTOCOLS to achieve the desired results. There was actually an example of this (albeit a bit hidden) in cell V3 of the InstanceNum worksheet in my original sample file. With this new example, though, you could try the following:

=UNPIVOT(B4:C6,,TEXTTOCOLS(D4:D6,", "),,1)

If you don't like that "ColumnID" is included in the final output, use CHOOSECOLS to remove it (see attached sample file).

The second example, I would say, is more closely related to my REPTA function, or even the PMTSUMMARY function that we drafted yesterday. As a matter of fact, you can use PMTSUMMARY to achieve the desired results:

=DROP(PMTSUMMARY(B14:D16,1,D14:D16,,1),,-1)

However, this function is somewhat overkill for this particular scenario because all that's really needed is TOCOL-IF(S)-SEQUENCE with or without CHOOSEROWS:

REPTROWS = LAMBDA(fields,number_times,
    CHOOSE(
        1 + (COLUMNS(fields) = 1) + (TYPE(number_times) = 64) * 2,
        CHOOSEROWS(fields, TOCOL(IF(SEQUENCE(, number_times), SEQUENCE(ROWS(fields))))),
        TOCOL(IF(SEQUENCE(, number_times), fields)),
        CHOOSEROWS(fields, TOCOL(IFS(number_times >= SEQUENCE(, MAX(number_times)), SEQUENCE(ROWS(fields))), 2)),
        TOCOL(IFS(number_times >= SEQUENCE(, MAX(number_times)), fields), 2)
    )
)

The syntax would then simply be:

=REPTROWS(B14:D16,D14:D16)

Cheers!