Did Professor Snape teach Harry's 6th year class any DADA skills that came in useful in the rest of the series?

Question

Snape was clearly a competent DADA teacher (as opposed to some of the others before him).

Is there any example in canon (books/Pottermore/interviews, or even movies) that show unambiguously one of the things taught by Snape to Harry's 6th year to come in useful to one of Harry's classmates in books 6 and 7?

This excludes anything that DA members are known to have learned in DA from Harry.

You may include items that are not 100% clearly shown to be taught by Snape, but which:

1. Were not shown to be taught by anyone else earlier

2. Were clearly something that would be taught in DADA class and not some other class.

3. Ideally, shown that the person using the skill would NOT know it until DADA with Snape.

Answer 1

The main example is the use of non-verbal spells. Snape teaches the sixth years non-verbal skills. Quite a few of the protective spells used, Harry taught in the DA, but Harry did not teach the DA how to perform them non-verbally.

‘... you are, I believe, complete novices in the use of nonverbal spells. What is the advantage of a non-verbal spell?’

Hermione’s hand shot into the air. Snape took his time looking around at everybody else, making sure he had no choice, before saying curtly, ‘Very well – Miss Granger?’

‘Your adversary has no warning about what kind of magic you’re about to perform,’ said Hermione, ‘which gives you a split-second advantage.’

_{Half-Blood Prince - page 170 - Bloomsbury - chapter 9, The Half-Blood Prince}