Dracaena marginata suckers? Aerial roots?
It's only been about 6 months since this tree was repotted but the tips are going yellow. Sure enough, the pot was crammed with roots, and one root coming out of a drain hole was turning green. Is this a sucker, like on a lilac shrub? I broke that one off, trying to turn it so I could put it back in the pot with that green nub exposed. But there were a couple other strange roots that looked like they had similar potential, so I did leave a few of them exposed to see what happens.