One of my favorite good finds-- is an on-line vocabulary program called "Get-A-Clue".
I like it because my son, aged 14 always wants to do vocabulary now.
And it is effortless on my part. I reviewed it, tried it out, watched him do it, and then he has been on his own. I check in on his progress from the teacher's log-in and see how he is doing--that is a nice feature.
They cover root words & prefixes, mythical & historical allusions, words commonly confused, foreign words, and strange & unusual words.
Check it out, they have a free trial too. And they have levels 1 through 6. Since my son started at level 6 and finished it, he wanted to go back and do level 5. They have a pretest that your student takes to determine what level to begin. But there may be words in lower levels that can still be reviewed.
I got it at the Homeschool Buyers Co-op.
Photo: screenshot of Get A Clue