jan Jasu o. toki!
I haven't got to post much on here since I made my account, but I've actually been working for the past few months on getting every toki pona word, origin, and definition down in my dictionary, so I might be able to help you on this.
So far it seems that the most common, Official words are the 123 listed under "Toki Pona words" on the main wiki, with noka (foot, leg) being more or less in a limbo. The word pu on there is also official I guess, but since it's undefined, it's not actually in use right now. The new words (apeja-shame, monsuta-monster(/fear?), pake-obstruct?) are also vaguely defined, and seem like legit toki pona to me, but they haven't been used much outside the threads dedicated to figuring out their meanings.
There's also the question of how legal it would be to use abolished/old poll words like pata (sibling), too, I guess.. But yeah, if you just stick to the official 123, and maybe noka, you should be able to say almost anything you want without having to bother with the other 16ish abolished/new words.
Yo estuve aquí.