If you're new to the game, you probably wont be engaged in super large scale pvp for a while, so there's alot of "raid" classes you can gloss over. These classes are mostly geared towards small scale, and less experienced players.
Note: Hybrid Classes such as Paladin or argent are excluded because I believe they are heavy noob traps that wont transition well into later game if you decide to take on large scale pvp.
Tanks- Abolisher/Skullknight
Abolishers are a great starting class for newer players. It consists of battlerage, auramancy, defense. Great for soaking alot of damage while controling your enemy. Not alot of straight damage but gets the job done.
Skullknights are more for raids, but can work in small scale. They have much less single target damage than an abolisher, but if used correctly can be far more annoying than your melee counterpart. Has alot of aoe crowd control. Consists of Occultism/Auramancy/Defense.
Magic Dps- Enigmatist/Daggerspell
Enigmatists are probably the most useful overall small scale class as a mage. They offer high mobility with alot of burst. On a basic level can be played effectively, but has a high learning curve to truly master the class. Consists of Sorcery/Auramancy/Shadowplay
Daggerspells dont have alot of movement or raw damage, but will teach you about the use of crowd control and positioning. Offers heavy control of the enemy, with witchcraft being the heaviest cc tree in the game. Because you do not have auramancy, and only shadowplay as your movement, you might often find yourself caught in a bad spot with no escapes. This class is mostly used for 1v1s, but can be useful in smaller scale pvp. Consists of Sorcery/Shadowplay/Witchcraft.
Note: Spellsinger/Spellsong are ommitted from this because while they have the highest burst damage in the game, they come with a heavy price of knowing how to position your character. Do not recommend for newer players.
Melee Dps- Darkrunner\Hexwarden
Darkrunners are the most played class in the game for a reason. Its got the fastest burst in the game with some of the highest mobility if used correctly. Doesnt take much to be good at, but you can tell a good darkrunner from a bad darkrunner. Transfers very well into large scale pvp. Consists of Battlerage/Auramancy/Shadowplay
Hexwardens have a tiny bit less damage, but offer alot of crowd control, similar to daggerspells. This class will teach you how to use your crowd control defensively, often peeling for your healers or squishy backline mages. Can be used aggressively if learned correctly. Consists of Battlerage/Witchcraft/Auramancy.
Healer- Cleric/Templar
Clerics are arguably the most useful healer in the game. With the combination of songcraft and vitalism, you have the potential for alot of big aoe heals, as well as solid single target healing. Consists of Vitalism/Songcraft/Auramancy
Templars are a mixed bag for me. Defense is almost never good on a healer, especially in large scale. However templar is a very good starting class for people who arent comfortable with their positioning as a healer. Once you get more comfortable with living and keeping everyone alive, you want to swap to cleric asap. Consists of Vitalism/Auramancy/Defense.
There are other very viable choices for small scale pvp, that are used frequently in large scale pvp, but require a little more extensive knowledge of how the game works before you tackle those classes. Hope this helps!
