There's some pretty big inconsistencies with tanking from dungeon to dungeon as far as tankbuster damage goes and when they show up or if they're even worth mitigating. in the level 50-60 dungeons, if you're adequately geared, the damage that comes from them is laughable for the most part

What I've found is that there's generally 3 kinds of tankbusters that you'll see

1. completely random busters, honestly no way of knowing when they'll do it. In particular for this kind I can only think of dohn mheg's second boss (unless I'm dumb but I swear I can never tell when it's going to come out so I end up getting chunked for 3/4 of my hp every time lol) and I'm sure there's others I can't remember right now

2. Stormblood starts introducing busters that tend to always occur after a set of mechanics, starting right away with sirensong's final boss. Every time the boss casts "morbid march/retreat," an instant cast buster almost immediately follows it, which is a fairly recognizable enough pattern when you've run it enough times to notice. The final bosses of shisui and bardam's mettle follow this pattern too, as do others I'm sure I can't remember off the top of my head

3. The ones you can actually see the cast for. I atleast noticed for shadowbringers, nearly every buster I saw casted sounded like one while I was running them blind, which was something I enjoyed, names that clearly indicate what's about to happen (The tickler, headcrusher, crippling blow, stonefist, rend, ripper fang, etc) Of course there's also plenty of the more odd ones you can't really tell that I still can't remember for the life of me (like most of mt gulg honestly)