I’d agree with ColonelKataffy, 1-12 are the good ones imo. The show definitely starts changing towards the end of those seasons but its still good. Just different from season 2/3.

I really enjoy the Mr Burns episodes. Three eyes on every fish, bart gets hit by a car, Burns’ Heir, Homer The Smithers, Mountain Of Madness, and The Old Man And The Lisa. (there are more but those are just the ones I can think of right now)

As far as ones outside of those seasons I’d consider grabbing the treehouse of horror episodes, they stay better for longer imo and from what I’ve heard even modern Simpsons has good treehouse episodes sometimes. There’s also some sideshow bob episodes after season 12 iirc so if you get involved with that plot line you might want to grab those too.

Also grab the movie, its worth a watch.