The 2024 Player's Handbook made species (formerly known as races) a far less crucial part of a Dungeons and Dragons character. It's not quite so exciting, then, that the next D&D sourcebook features five updated species options. Still, with some careful planning, these can be assets to your future character builds. Here's a quick overview of the upcoming Eberron species and some tips for optimizing them.
Bear in mind that Wizards of the Coast hasn't revealed the full rules for these DnD races. The D&DBeyond article shared on July 15 gives a broad overview of the changes rather than the complete, crunchy details. Still, we can make some educated guesses about the DnD classes they would pair best with.

Changeling
Changelings have barely changed since their iteration in Monsters of the Multiverse. The only new feather in their cap is advantage on Charisma checks while in their shapeshifted form.
Naturally, this lends itself to any Charisma caster that wants to minor in Face studies. The Bard is the obvious choice here, given their tendency to hoard skill checks like a dragon with too much gold. It also encourages you to stay in shapeshift form all the time, because you never know when you'll need to make a sudden Deception check.
This update to the Changeling basically gives the species a free version of the Actor feat. They don't get the +1 to Charisma, but if this new ability applies to all Charisma checks, they have a bit more skill flexibility than they do with Actor.
Kalashtar
Kalashtar has always been the go-to species for defending yourself against spellcasters. Resistance to psychic damage and advantage on Wisdom saving throws were a serious boon to frontliners who might otherwise struggle in these departments. This remains true, but now the Kalashtar is even better against magic users.
That's mainly because they're now classed as Aberrations rather than Humanoids. Spells that only work on the latter category, such as Hold Person, will have no effect on the Kalashtar going forward. It's a bit of a situational buff, but it could save your skin. Barbarians and Fighters should take notes.
The new Kalashtar can also swap proficiency in one DnD skill per long rest, which is a nice boon regardless of your build. Their innate telepathy has also seen an upgrade, as it can now target multiple creatures, and you no longer need to see them.

Telepathy is particularly handy for party Scouts, so Dex-based characters like the Ranger, Rogue, and Fighter will have plenty to work with. However, there's an elephant in the room here that we should really address: the Psion.
D&D's newest class, which is still in playtesting, has made telepathy a big part of its identity. Psions get five feet of telepathy from level one, but they can spend their class resource, a Psionic Energy Die, to extend that reach. There's even a Telepath subclass that, at level three, can extend that range further and target multiple creatures.
The original Kalashtar had telepathy equal to 10 times their level, and they didn't have to spend resources to use it. If this all stays the same and the new rules give the Kalashtar multiple targets, this species is going to make the Psion look a little behind the times.

Khoravar
Now that the Half-Elf has been axed from the core rules, the Eberron-flavored Khoravar has stepped in to fill their shoes. They're basically still a Half-Elf with all the usual trappings - Darkvision, Fey Ancestry, and so on - but they've got a few new tricks now they're a separate species of their own.
The new feature that's worth writing home about is Fey Gift. You start out knowing the Friends cantrip, but on a long rest, you can swap it with any Cleric, Druid, or Wizard cantrip. You won't get access to leveled spells like you would with an Elf or a Magic Initiate feat, but you gain a huge amount of flexibility.
This is particularly attractive to magic users with limited spell lists. Warlocks are one of the first classes that come to mind, though bear in mind that these cantrips might not synergize with your Eldritch Invocations. We need to see the full rules, but unless your Khoravar cantrips can count as a Warlock cantrip, you won't be using Fire Bolt or Sacred Flame with Agonizing Blast.
Still, a Warlock (as well as a Ranger, Eldritch Knight, and many others) can pick up a strong-as-hell cantrip this way. Shocking Grasp, Booming Blade, Ray of Frost, and Word of Radiance are all handy damage-dealers, while Guidance and Mage Hand are utility must-haves. Plus, if you're interested in Shillelagh builds, that's on the table too.
The Khoravar's other species ability is less interesting. It allows you to turn a failed save to end or avoid the unconscious condition into a success. That can be pretty darn handy in combat, but once you use it, you must wait 1d4 long rests before you can use it again. That inconsistency is a real mood-killer.

Shifter
Basically nothing has changed for the Shifter, as un-sexy as that is to write. The only difference from the version in Monsters of the Multiverse is that you can choose between two DnD sizes when shifting.
Given that shifting can offer temporary HP, extra speed, or defense against advantage, this species remains appealing for its defensive options. Tank-y frontliners and squishy spellcasters who want to try out being a part-time werewolf should sign up to become a Shifter, though we'd argue there are plenty of Player's Handbook species that are just as good at keeping you away from death saves.
Warforged
The Warforged was always a tank-y species option favored by classes like the Artificer, Barbarian, and the occasional Cleric. Most of Wizards of the Coast's changes seem to be to the wording of the Warforged, so its role in the world of DnD character builds hasn't changed all that much.
One major change is that Warforged don't gain exhaustion from dehydration, malnutrition, or suffocation. This makes them well-suited to a DnD campaign that features a particularly harsh dungeon crawl or exposes the adventurers to the dangers of extreme weather.
Additionally, Warforged now count as Constructs rather than humanoids. As already discussed, this means they'll be safe from spells that target humanoids, further adding to the defensive benefits they can offer a low-level adventurer.
How do you feel about the updates to these species? We'd love to hear your opinion in the Wargamer Discord. Or, if you'd like to learn more about Eberron: Forge of the Artificer, head to our DnD release schedule guide.