Are you an altoholic? If your play style favors hopping from one toon to the next at a moment's notice, you'll want to take a look at these alt-friendly MMOs.
Guild Wars 2
Guild Wars 2 is one of my favorite MMOs for several reasons. It's also one where I have routinely played several alts, with a warrior, elementalist, and mesmer at max level. GW2 gives you several character slots, shared bank and crafting storage space, and shared gold and tokens. While world completion is tedious to finish with even one character, playing alts will let you start in all the main cities and explore some variety in the map early in the game without having to take a single character through all of it. Getting through the harder areas will still require you to level up for survival, but if you love to explore, playing alts will give you a quick fix for this.
The main quest line is also different for each starting race, although it converges to a single story line later. Playing alts will let you experience all of the story. In a similar fashion, GW2 offers classes such as necromancers, mesmers, and engineers, which are not your standard fantasy classes. Try these out with alts and decide how far to go with them later.
WvW play also caters to some unique class builds that can be used strategically. My mesmer was not a great choice for PvE play, but had abilities in WvW play that were not found in other classes, such as portal. Customize your alts for different roles - tank, healer, etc. for dungeon groups or PvP play. GW2 allows you to switch to another character quickly.
While ascended gear has made it tougher to fully equip your alts, exotic gear is definitely within reach. Timers for world-bosses are account-bound rather than character-bound, but unless you are working on a legendary item, most players don't need to finish all of these every day.
If you aren't convinced that GW2 is an alt-friendly MMO yet, once you've been playing for a year, you'll receive a scroll that allows you to instantly bump a character up to level 20. What do you have to lose by rolling up a new character?
Black Desert Online
Black Desert is an alt-friendly MMO if you love crafting and trading (which I do). The game allows plenty of character slots so that you can try out the different classes, with more still being added. Storage, contribution points, max energy, NPC amity, and many other features are shared account-wide. If crafting and trading aren't your thing, then playing alts in BDO may not have as much appeal other than letting you try out the skills and abilities for the other classes. All the classes start in the same area and follow the same main story.
Once you have leveled your first character a bit, create some alts. This is most helpful if you have explored the node system, invested contribution points, and set up a network of linked nodes. Pick which type of crafting or trading you want to focus on and hire some workers to start building your empire. Now you can use your alts strategically in different cities to gather materials and fill your storage with whatever your local crafting requires. If you try to do this with a single character, you will have to travel across the world more often because Black Desert doesn't offer any type of fast travel. Take your main out to quest and explore and switch over to the alts when you need to shift inventory in a distant city, cook beer for your workers, or rearrange your invested nodes.
Play your alts for fun and complete quests to accumulate even more contribution points and energy. Even though repeating quests will be well, repetitive, the early ones are easy and you can build up points quickly. Enchanting can also benefit from using alts, allowing you to create higher level items with a lower chance of failure.
Star Wars: The Old Republic
Star Wars: The Old Republic is a great alt-friendly MMO for many reasons. The game gives you plenty of character slots, and the replay value of the main story is one of the best reasons to play alts. For free-to-play gamers, you only get two character slots, but if you subscribe at a certain level, you can have up to 40 characters per server! SW:TOR offers eight different main story lines, with each one an immersive experience that truly lets you feel like you're a Jedi, Sith lord, or bounty hunter.
Legacy gear, bank, unlocks, and warzone commendations are all account-wide. Reputation is also shared among characters, and more emotes and perks are available, depending upon your alts.
While Eve Online may not seem like an alt-friendly MMO at first glance, playing this game to best effect will involve the strategic use of alts. For one account, you have three character slots to fill, which isn't that many, especially compared to other games. Also, you can only train skills on one character at a time, which will slow your progression on each one.
Your alts in Eve are used similarly to those in Black Desert, by training particular skills, and assigning them specific local roles. Alts can be used to price check, make posts, or generate income through planetary interactions. If your main is part of a warring corporation you can use your alts to accomplish freight hauling or mining. While your main character is fair game in this situation, there are consequences for attacking any of your alts because they aren't involved in the war.
For faster progression using alts, you have the option to pay a monthly fee and train more than one character at a time. Another strategy is to use a separate account and then associate these alts with your main by placing your characters in the same corporation or through trading.
An Honorable Mention
An honorable mention for being an alt-friendly MMO goes to the defunct game City of Heroes. The character creation scheme in this game allowed billions of costume combinations, with numerous primary and secondary power sets for additional customization.
Other Alt-Friendly MMOs to Explore
The factors that make an MMO alt-friendly will vary depending on your play style. Other games that offer some incentive to play alts include Champions Online, EverQuest 2, Dungeons and Dragons Online, Tera, and World of Warcraft.