John Gill Commentary Jeremiah 29:2

"(after that Jeconiah the king, and the queen-mother, and the eunuchs, [and] the princes of Judah and Jerusalem, and the craftsmen, and the smiths, were departed from Jerusalem,)" — Jeremiah 29:2 (ASV)

After that Jeconiah the king Of Judah; the same with Jehoiachin, who was carried captive into Babylon when he had reigned but three months: and the queen; not Jeconiah's wife, for he had none; but his mother, whose name was Nehushta, and who was carried captive with him, (2 Kings 24:8 2 Kings 24:12).

and the eunuchs; or "chamberlains" to the queen; the Targum calls them princes; these were of the king's household, his courtiers; and such persons have been everywhere, and in all ages, court favourites:

and the princes of Judah and Jerusalem; the noblemen and grandees of the nation:

and the carpenters, and the smiths, were departed from Jerusalem; whom Nebuchadnezzar took with him, partly for his own use in his own country; and partly that the Jews might be deprived of such artificers, that could assist in fortifying their city, and providing them with military weapons; (See Gill on Jeremiah 24:1).