Answer: more often than naught.
This one is a fairly broad question, but the answer is almost always, yes. Steamed, flashed and packaged whole, crushed and chopped tomatoes are almost ALWAYS vegan. I haven’t found any brands that have non-vegan additives. Pre-packaged pasta sauces are different. Obviously, you should avoid meat and sausage additives. Some brands put cheese in even their “traditional” or “classic” sauces, like Ragu. Ragu uses romano cheese in almost all of their sauces.
In summary, most of these are going to be vegan. But be careful to check the ingredients for meat, cheese and honey. These are the usual culprits.