Every block (I think). I will not include non-functional blocks such as "all at once" and "hide all sprites" because it should be self-evident that those are useless.
This is, in my experience, about how often all of these blocks will be useful. Feel free to criticize or agree, but do so respectfully. NOTE: Every block has SOME usefulness. But these are my recommendations if you're in the business of making great games.
