"Other" at Col. 1:16
"For through [Jesus] all things were created in heaven and on earth" - MLB.
"by means of [Jesus] all [other] things were created." - NWT
The KJV also adds words at many places in the scriptures and frequently [but not always] signifies these additions by italicizing such added words. In fact, all Bible translations add words to make the intended meaning of the original language clear to the readers of another language. The NWT usually indicates added words with brackets [ ] as at Col. 1:16, 17 with ["other"].
ALL Bible translators supply needed words in accordance with their own understanding of what meaning the Bible writer actually intended. Any serious Bible student knows this elementary fact. For instance, you can see that the KJV translators (and NIV, NKJV, TEV/GNB, Beck, etc.) supplied the word "other" at Acts 5:29 (and rightly so) even though it is not actually written in the original text. (Also compare KJV at Job 24:24).
Since it is obvious that Christ did not exist before himself, nor before the Father, these two, at least, have to be excluded from "all things" at Col. 1:16, 17. Therefore, the very trinitarian NAB and LB have properly added "else" to this scripture. This is the same thing as writing "before every [other] thing".
Certainly it is not wrong from a grammatical viewpoint (nor is it a "dishonest rendering") to add "other" as the NWT has done at Col. 1:16, 17 (and the LB and the NAB have done with "else" at Col. 1:17) and so many trinitarian translators have done in other similar situations.
Compare these examples:
The highly regarded NASB (and NEB; REB; NIV; JB; NJB; NKJV; ETRV; BBE; NLV; MKJV; MLB; Darby; Beck; and Young’s) translate Is. 45:14 - "There is no OTHER God." The word "other" is not in the Hebrew OT manuscripts and has been ADDED by the translators (and rightly so). The NWT renders it "there is no [other] God." RSV and NRSV have also added "other" and also another, similar phrase: "there is no OTHER, no god besides him."
And we find NEB; REB; NJB; NAB (‘91); GNB; and LB (for example) have honestly added "other" at Ezek. 31:5 to show that a certain tree towered above "all other trees" whereas KJV, NASB, RSV (for example) have it towering "above all trees." Since it does not tower above ITSELF, the Bible writer obviously excluded it from the phrase "all trees" (even though it is also a tree itself and a part of "all trees") just as Col. 1:16 excludes Jesus from all other things.
For more, see
NWT - "Other" at Col. 1:16