The days of when the only way for you to have a wild symbols appearing on any of the paylines you have chosen to put into play on a slot have long gone! For you will have plenty of different types of slot games available to you online which can randomly add wild symbols onto the reels either during the base game for via some form of bonus game.
There are several slots available online at various different casinos sites that will have some form of randomly award bonus game, which is usually triggered as soon as you click on the spin button to send a base game spin into live play.
Those bonus games will then see one to five of the reels becoming completely filled with wild symbols, and as such it will be possible for you to get a screen full of wild symbols spinning in on those slots during the bonus game.
However there are other ways that wild symbols can be attached to the reels of some slot games you are playing, and one slot that offers random wild symbols is the Lights slot game found in sites utilizing the NetEnt range of slots.
When you are playing the Lights slot game soon every single base game spin you are going to find wild symbols floating around the screen as the reels are spinning, and 2 to 4 of those wild symbols will suddenly attach themselves to random reel positions at the end of the spin.
What makes that slot a very appealing one to players is that when you trigger the free spins bonus round the number of random wild symbols that will be guaranteed to appear on the in view reels increases, and as such you will find on ever single free spin played off between 3 and 6 random wild symbols will be added to the reels.