Yet

as (of) yet always in negatives formal phrase

used for talking about something that has not happened or been done up to now

• A deal is still being worked out, but as yet nothing is finalized.
• Police stated that there have been no arrests made as yet.
• The report remains unfinished as of yet.

yet again : for another time : again
• They arrived late yet again. [=once again]


the best is yet to come:

• ("How're things?" – "Things are really getting tough." – "Don't worry. The best is yet to come.")

When you encourage somebody to be patient

• The best part is still ahead.    (You're young. Your life has just begun. The best is yet to come.)

When you hope something positive will happen

just yet : right now - used in negative constructions to say that something is not done yet or true yet but will be soon
• I don't have the table finished just yet.
• “Are you ready to leave?” “Not just yet.”

 "I don't have the table finished just yet." This has the nuance that (a) some small difficulty has arisen but the speaker is dealing with it and/or (b) there will not be a great delay in the completion.

"I haven't finished the table yet." Says exactly that - No extra information.