Thanos killed a lot of people - and presumably a lot of cows, dogs, fish, bacteria and plants since he was wiping out half of existence - so it's probably fair to assume that a lot of the supporting and background characters we've seen in the first ten years of the MCU are gone. Half of them in fact.
Peter Quill's grandfather? Maybe dead. The Broker? Possibly a goner. Miriam Sharpe? Not necessarily alive. Peter Parker's teachers? It looks decidedly iffy. But we generally don't ten to think of those characters, because they don't have a big impact on the story and we're unlikely to see them in any meaningful way every again.
Different entirely are those characters who have actually mattered in the past, but were still left out of Infinity War. Luckily though, HuffingtonPost sat down with the Infinity War directors and demanded to know the fates of some of those very characters, with surprising openness.
So who survived and who didn't?
According to Joe Russo, Hulk's one-time best girl Betty is "gone," which is handy because dropping another pointless romantic subplot into the MCU at this stage would have been a bad idea.
Well, Banner appears to have forgotten her entirely, so the ripples in his life won't be particularly major, but they might well be in her father's. Assuming he too survived.
General Ross needs a reason to turn his back on his pro-registration ideology, and something as cutting as a personal tragedy might be the catalyst for him softening his stance and dropping the Accords entirely. A dust daughter will do that sort of thing for you.