This is an incomplete list of series or bodies of work which are officially free to spoil. Enough time has gone by in enough markets that only one or two humans are left who haven't seen/read it. We feel for them, but not enough to make our wiki look like some sort of weird Swiss cheese.
Spoilers off for:
- If the copyright has expired, or if it predates the very concept of copyright, it's probably free to spoil. In the vast majority of countries, this roughly coincides with anything Older Than Radio. The cat is out of the bag for all of William Shakespeare's plays.
- Anything from myth (e.g., Oedipus), religion (e.g., The Bible), or even legends (e.g., Robin Hood). If it's Older Than Dirt (or at least Older Than Feudalism), it's definitely OK. That said, occasionally spoiling Biblical events (Jesus dies but comes back to life) can be very funny. Just don't go overusing it.
- If you spoiler-tag a fact, something that happened in Real Life, you have our full and express permission to punch yourself in the face. Unless you do it to be funny, then the person who doesn't realize it's a joke and angrily deletes the tag has the face punching permission. Obviously, this applies to any works based on true stories (unless they're only inspired by the facts and take significant liberties with the historical record).
- Quotes from a work. Either it doesn't need spoilers, or it doesn't need to be quoted; use ellipses (...) if need be.
- If the article is an episode recap, no spoiler font. The nature of the thing is to give detailed information about the episode. A person who wants both all the details and to not see spoilers is not a person we can help. However, do not add spoilers for future episodes, even under tags. Those go on the later episode pages. Foreshadowing is a special case — state only what is doing the foreshadowing, not what is being foreshadowed.
- Fridge, Headscratchers, and the various Moments subpages (Tear Jerker, Moment of Awesome, etc.) are for post-viewing discussions. Spoiler tagging there defeats the purpose of the articles. You shouldn't be going there if you are worried about them.
Incidentally, if big blocks of whited-out text turning everything into Swiss cheese look needlessly hideous to you, you can set it up so that spoilers are always visible by going to your profile or just by hitting the spoilers switch to the right near the top of the page. You could also check to see if the spoiler text really has anything to do with the trope. If it doesn't, delete it. Alternatively, turn on "Night Vision" mode to have the spoilers turn black instead of white.