Some do and some don't. Any spell in the fantasy will not work, nor will any spell that says it will swap bodies, change your gender, make you fly, etc.
When looking for spells on this site, use common sense. If it sounds impossible or improbable then it is. If you can't do it without the use of magic then yo most certainty wouldn't be able to with magic.
As you know, this is a real magic site and it has spells. Few of the spells will work, and few will be even pointless to try to cast.
There are real magic spell in this site,and they definately have a good potential to work. But only potential. The proper spell is one of the criteria of the success of casting a spell, but only one. You also have to know your basics such as: Grounding, centering, directing and manipulating energy. you also have to know about spell casting, and about how magic really works. Few things are optional, but they help the spell to be done properly, such as: moon phases, candles, colours, magical tools, etc. But as I said, the proper spell is one of the things that make a spell work properly. Every logic and real spell has a good potential to work if you know what you are doing.
But there are also spells that do not even have the potential to work, no matter what you do. Such spells are pointless, and will waste your time and energy. The spells are called fantasy spells, or as we define them "fluffs" or "fluffy spells". You have to use your logic sense, maturity and understanding of magic to recognize such spells, and to tell the difference between them and real magic spells which have the potential to work properly.
Now, as I said many spells here have the potential to work and many do not.
Personally, I do not use the spells of this site, but I am not saying that the are not good enough to try. Personally, I find the spells that I make by my own as more comfortable to cast, and more effective. But this is my personal opinion and preference though, and I am not saying that the spells of this site do not worth a try.