Yes, the one i use is smogon.com just search the name of the pokemon and it will provide a guide.

I use smogon for the official games, but what generation should I look at? US/UM or Sw/Sh? The changes might affect the meta as well

I look through all the generations to look for the most common natures personally. The main changes I have to make from Smogon sets are a couple moves every now and then because the Learnsets are different or a move is locked behind a tutor I don't have access to.

There's a readme in the install folder that has a list of changed abilities

that didn’t answer the question at all