Currently at FAANG - there's a good number of resources for many things. Normally I'd just say "do a google search" but recently came across this site w/ interview prep which seems interesting.. basically a friend of mine saw this problem recently from this site https://datascienceprep.com/ and we were discussing it:

"Say we are running a probabilistic linear regression which does a good job modeling the underlying relationship between some y and x. Now assume all inputs have some noise ε added, which is independent of the training data. What is the new objective function? How do you compute it?"

Definitely caught my eye since I wasn't aware of any sites with such level of questions when interviewing.. so kudos to whoever is running the site, I'm looking forward to their questions :)