league-of-legends
I was wondering why Nasus, Nunu AP, Volibear are not considered as viable solo top?
I mean, they are all decent and have sustain as well as a good snowballing potential. That's why I don't get why they're rarely ever played in competition or even in high ELO solo queue games.
The following champions are considered support champions, in the sense that they will either heal/shield an ally and/or buff their armor/magic resist/movement speed.
Janna excels in supporting teams.
She has many support abilities:
Howling Gale which launches enemies into the air in a line.
Eye of the Storm shields an ally for a determined amount of damage and gives a damage buff, and it is the only shield capable of protecting turrets.
Moonsoon is a teamfight changer ability as it aoe heals your team and blows away enemies in Janna's ability ratioJanna as also a natural passive that is buffs the movement speed of your whole team.
Tailwind grants 3% move speed buff! 
Karma can contribute with great magic damage bursts. Additionally, she has a single target movement speed buff. Karma is a special support champ in the sense that she does not posses an ultimate ability per se, but her ult, Mantra, gives her a bonus effect on all of her other 3 spells:
Heavenly Wave + 
Mantra = AOE Heal in a cone in front of Karma
Spirit Bond + Mantra = Single Target Move Speed Buff x 2
Soul Shield + Mantra = Very High Scaling shield + Aoe Magic Damage around the shield bearer, in my opinion her best ability of all. 
Kayle makes an ally invulnerable to all damage for 2-3 seconds! Additionally, she heals allies and slows enemies, making her a very nice support pick. Unlike Janna and Karma which build defensive and AP items, Kayle builds Hybrid items like Hextech Gunblade and Guinsoo RageBlade.
For a quick overview of her abilities:
Divine Blessing heals up an ally and grants a movement speed bonus.
Intervention grants invulnerability for 2-3 seconds, which can completely alter the course of a team battle if used well. 
Lux is considered a support/mage. She can tear up teams with her chain of abilities, possesses a 2 unit root, AoE slow, and an amazing Ultimate.
Additionally, her main supporting ability is:
Prismatic Barrier shields an ally for damage. 
Morgana is just like Lux in that she is a support/mage. However, she is considered a better support for the shield she grants:
Black Shield is a very unique shield that blocks magic damage and any negative effects: all snares, silences, blinds, etc. This shield scales with 80% of her total ability power. It is a total carry protector and game changer skill.Additionally, Morgana has a single target root, a magic resistance debuff AoE DoT, and a powerful AoE stun.
I mean, is Sona good for help?
Sona is the queen of support in my opinion, closely followed by Soraka. All her abilities except for the ultimate give your teammates a buff and she can not be ignored damage wise.
Hymn of Valor is an aura granting a buff to damage and ability power. 
Aria of Perseverance is an aura that increases armor and magic resist to allies. On cast, it will heal the most wounded ally nearby. The Powerchord bonus decreases total damage output of the target by 20%
Song of Celerity gives a temporary movement speed buff to your allies, in addition to the aura which grants a fixed movement speed bonus! Can we count Soraka and why?
Soraka is one of the oldest support champions, and one of the most powerful ones. She has a single target heal plus armor buff and the ability to grant mana to an ally.
Astral Bleesing heals for a decent amount while granting 20-80.
Infuse grants mana to an ally. No other hero can boast an ability like this.
Wish is a global heal. The epitome of an incredible support heal.
Consecration, her passive, increases magic resistance for nearby allies by 16.Is Taric a tank, or a good support champion?
He can be both. Taric's base armor and health and armor/level and health/level increase are very high compared to all other support champs.
Taric can heal and has an Armor Aura, Damage Aura, and a Stun, which makes him a reliable support character. However, one of his downsides is being a melee character unlike many of the others mentioned.
Imbue, if casted on an ally, heals Taric and your ally. If casted on Taric, he heals himself an additional 40%.
Shatter is an aura that increases allies' armor by 10-30 and increases Taric's by double this amount!
Radiance heals Taric by an amount per second while granting an aura that increases attack damage by 15-45 (and double that on Taric). Make sure to use while taking down towers and in team fights!
Zilean is an amazing support champ with the unique ability to revive champions.
He is a great addition to a team because he posseses:
Time Warp is a single target Speed Buff/Debuff
Chronoshift revives a fallen enemy with scaling (200% of AP) restored HP and Mana. That's like fighting a 5.5 vs 5 :)
Heightened Learning, his amazing passive, gives all allies an 8% bonus to experience gained!As you can see, LoL offers you a wide variety of support champions to play.
Which champions are viable to play nowadays on LoL as support?
Depends completely, for instance:
Your team has an AP carry, AD Carry, a tank and a Beefy Meat Shield champ, what are you lacking? Since you already have an AP carry you can play a pure support champion like Taric, Janna, Soraka or Zilean.
Now if your team has already a Tank, an AD carry and a Jungler, your team will need some magic damage source, then playing Morgana, Lux or Sona will make the team composition solid.
If you want a current metagame opinion on which are the most played support champions, I would say Sona, Karma and Zilean.
Doran's items are excellent for early game.
When you should buy ?
- If you are having a slow or bad early game.
When you should stop buying ?
If you start your game with a good advantage (let's say 3-0-0 before 5min or any other great start set), you can skip the Doran's itens and go for others like Brutalizer or even BF Sword.
When you get 2 some times 3 (but this is kind rare), you should stop buying them, because the game will probably be going to mid, and switch lane phases.
Should I store money until I get gold enough to buy BF sword, instead of Doran`s ?
No, If you do not buy items, to scale with your level, you will be too much week (works as when you are being too much harass that you can't farm at all. So you do no damage in few minutes)
Best Answer
Nasus:
Nasus is a great late game champion if he can safely farm. The main problem with Nasus is that he is countered by a lot of champions. In lane his main worries are Gangplank, Gragas, Irelia, Lee Sin, Nidalee, Renekton, Ryze, Skarner, Tryndamere, Udyr. They all have to ability to be aggressive on you. Unfortunately, Nasus is not very good at applying pressure back and this usually leads to a lost lane. Nasus also can be easily kited in team fights.
Nunu:
Nunu has great sustain in lane and can even harass a little bit with his snowball. He also has a speed buff to make escapes and two different ways to slow the enemy (on being AoE). However, there is one major flaw to AP Nunu and that is he is not very useful in team fights. His snowball may be good for poking and harassing. But since it is on a 6 second cooldown, it can't deliver consist damage in a teamfight. His ultimate is one of the best in the game if it connects. But most league of legends players know to cancel your ultimate with CC or can escape from it. Essentially, AP Nunu is a support with no constant damage for team fights and bunch of gold from lane that could've been used on a different champion.
Volibear:
I'm not too familiar with Volibear so this section may not be as accurate as the Nasus and Nunu sections. Volibear can be good in lane against some champions. His passive makes his enemies commit to him thinking he is low in health when really he heals a ton back. He also provides a fear and a throwback similar to singed. However, Volibear has to get into the enemy's face to deal damage. Which wouldn't be a problem if he wasn't kited easily. He has trouble against ranged champions who can keep him far away. His cooldowns on his abilities are fairly high (the lowest being 8 seconds on Rolling Thunder if you max that skill first which you most likely won't. Otherwise it's 12 seconds if you put one point into it.) Enemies can literally just walk away from his ultimate if you don't have you abilities ready to CC him. Finally if Volibear doesn't dominate his lane, he can fall off late game and be kinda useless.
Final Note: All of these champions can be viable for competitive use if played correctly and against the right champions. Nunu can out poke the enemy champion and shut them down in lane. Nasus and Volibear can be played if they have the right matchup in top lane. For this reason you never want to pick these champions before you know who the enemy's top lane is (Nunu is a little safer to pick because you can always just play him in the jungle or support). It all comes down to the picks and bans.