SendAppearanceEffect

[trevius]

All of these effects seem to be based on the size of the NPC. The small effects may be barely noticeable if at all for certain NPCs, but they should all still work just fine. I suspect that the issue you are seeing is probably related to some NPCs in the Database being set to a size of 0, which shows them as size 6 in game, but this effect might still think they are size 0, and thus now show an effect. I haven't tested this yet to verify, but this is my current theory on the issue you are seeing.

For the permanent affects, I suggest you specify a specific $client at the end of the command so it only sends to 1 client at a time. That way, when players zone in, you could send it to them at that time and not again, so everyone sees the effect without the stacking problems.