Currently there are 12 different types of summoner spells. Here we’ll take an in-depth look at them all and why you’d want to take certain ones over others. I’ll start with the most commonly used ones and work down from there.
Flash – A very, very useful escape tool as well as engagement tool. Flash allows you to teleport immediately to wherever your cursor is (So be careful when using this that you don’t flash in the opposite direction that you wanted to). Flash can take you over most walls in the game. Note that if you try flashing over larger walls, as long as your champion was going to land halfway past that wall it will then make it all the way over. Most every role will take flash as it gives them a quick escape and easy way to catch up/run into a fight. Flash is very useful but don’t rely on it to be there all the time. It has a very long cooldown and should be used carefully. Make sure you’re always wary when your flash is down because you’re much more suspect-able to enemy attacks.
Ignite – Ignite is a powerful spell that deals damage over time to a single target. Champions that need early kills or have a large kill potential early game will usually take ignite. This goes for most mid laners and top laners that have a strong early game. Some aggresive supports take ignite as well in order to try to get a quick and early kill in their lane. Ignite also reduces incoming healing by 50% so if you know you have an opponent who has a lot of heals or health regen consider taking ignite and using it at the beginning of the fight to stop them from healing all the damage you deal.
Smite – This spell is ESSENTIAL for junglers. It deals true damage to an enemy minion or neutral monster. It is used to help clear the jungle as well as secure objectives and buffs.
Ghost – Ghost is another movement summoner spell that increases your movement speed greatly. Most champions will take either ghost or flash depending on the champion/playstyle. Champions that need to keep up with/outrun their opponents for a continuous amount of time will usually take ghost. This summoner spell also has a much shorter cooldown than flash. Some champion examples that take ghost over ignite are: Singed, Udyr, Dr.Mundo.
Heal – Heal is run consistently on ADCs. Heal gives you movement speed as well as healing you and one ally a certain amount of health. Afterwards though, all incoming healing is reduced for a short period of time, so you generally only want to run one per team, or at least one per lane.
Exhaust – This spell is basically the opposite of ghost. It reduces enemy movement speed, damage dealt and attack speed for a short duration. This spell is commonly seen on supports in bot lane because the attack speed debuff is so strong. It is also sometimes taken for junglers, and mid laners that need to keep the enemy close to them.
Teleport – Teleport will allow you to move to any allied ward, structure or minion on the map. It is greatly used for top laners because they are so far away from early/mid game fights. As well as choice mid laners who would benefit more from getting kills in other lanes rather than 1v1ing their lane.
Cleanse – Removes all disables and summoner spell debuffs affecting your champion and lowers the duration of incoming disables by 65% for 3 seconds. This can be very useful against teams with a lot of lock down when you have low mobility or no strong escape.
Barrier – This is usually run with Flash and is taken for champions (usually long range mages) who shouldn’t be in range to cast ignite. It gives more extra health than heal does. Also, considering your ADC is probably running heal, it is not a good idea to take two.
Clarity – Not usually seen, it restores your mana and an allies mana for 40% each. I would rather suggest you learn to manage your mana costs and just build 1 mana regen item if you really require it.
Clairvoyance – This was a commonly seen spell in season 2 but rarely seen anymore. It grants vision in a small radius on the map at your choosing. It can be used to scout the enemy jungle and keep you safe or plan for invades.
Garrison – (Not available on Summoner’s Rift). For an Allied Turret: Grants massive regeneration for 8 seconds. For an Enemy Turret: Reduces damage dealt by 80% for 8 seconds. Even in dominion it’s a rather lack luster spell, but if you like it go for it.