Can I create a list in the Comments Field

[LyricsLover]

Yes.

You can use the Manage-Button (#4) for your custom list values

for every Tag Panel field:

@Florian

Every field on the Tag Panel can have custom values added to its drop-down list.

(I don't see what would be the advantage of custom list values for fields like TRACK or UNSYNCEDLYRICS for example. But technically, it is possible).