Source post compiled by fishers64, suggestions by many BZPers. Quotes of original suggestion posts included there.
Matoran of the Green (missing prefix and elemental trait )
For Prefix: Bo-Matoran, Gre-Matoran, Vi-Matoran
For elemental trait: skills in cultivating plants, natural affinity for plants, causing plants to grow when around, enhanced reflexes, plant life growing in armor, enhanced senses, ability to manipulate plants (crossbreeding, etc), ability to tell things about plants like whether they are poisonous.
The fanon Expanded Multiverse will likely adopt whatever is chosen in these polls as EM-canon, subject to final call by Swert and myself. (In the case of prefix, the previously established ones, if different, may be considered alternates.) I would also suggest that fans consider treating the winners as "headcanon" to use in fanfics, though ultimately such decisions are up to each fanfic writer.
Note: It is well-established already that the term "Green Thumb" is very popular for trait, however the exact definition of this term has never been universally agreed-on, so this poll is sort of to try to pin that down, though if you don't like the term that's fine too. If anyone has further thoughts on that you may offer them here in addition to the actual poll questions.