First of all, there are no "top three spells of all time." Different witches cast different spells for different reasons. Some witches don't even cast spells.
You are new, so I would suggest checking out the General Info section of the forums and then reading the stickied threads (the ones with red thumb tacks next to them). That will give you a good starting point, and you can go from there. I would not suggest starting with spells just yet.
Re: Top spells?
By: prsona / Knowledgeable Nov 17, 2015
Post # 7
How many spells? Countless. Someone made up all the ones which you will find now, many people make theor own in stead of using one pre-made, and anyone can make their own. That makes the number of spells in existance limitless, as the variables are undeterminable.
A spell is not what is magic; it is a ritual to direct one's energies and intention towards the purpose for which they want a magical result. It opens up the possibility of what may be done as a spell or ritual to basically anything.