In 3ed, the races generally look like this:

+2 to a stat, -2 to a stat. The PHB stats are never super optimized- like you don't get +2 strength and -2 charisma.
+Tiny modifiers to a couple skills situationally. These skills don't have training required to use, so they are actually useful.
+A supernatural trick or immunity or something.
+Their native language as a language in addition to Common.
+Possibly weapon familiarity, which usually is limited to martial weapons. This is an unusual choice, as it never helps trained warriors of the race, but often gives a small advantage to classes who are deliberately limited to simple weapons plus some extra-shitty set of martial weapons. For instance, being longsword trained doesn't help a wizard (who can't stand in melee without becoming an avant garde art project focused on the color red), doesn't help the elves fighter (who learned longswords in fighteryschool), but could definitely help a rogue or monk or something who is otherwise limited to agricultural tools and things that would otherwise be used at the dinner table)
+Darkness? Lets make that super complex where some people can see stuff to a certain range, and others have double radius on light sources. Except humans, those are the only creatures in the fucking universe that can't see in the dark. Worthless fools!
~Small: If the creature is small, its -2 to a stat was always in strength. Being small gives immense penalties on unusual combat situation like grappling, but gives a +1 to AC in general which is good. Being small makes you slow, which is really shitty.

In Pathfinder, we had a much better (IMO the best) take on the races. They ended up like this:
+2 to a physical stat, +2 to a mental stat, -2 to a stat. The PHB stats are allowed to be a little optimized within this- +2 Dex, +2 Int, and -2 Con isn't perfect, but if you are an elven wizard that +2 Dex will definitely help you. Pathfinder published the Advanced Race Guide or whatever which gave an idea how +2 to two physical stats and -2 to a mental stat was generally better than +2 to one of each and -2 to a physical, and even gave you some sense of that magnitude- including how good weapon familiarity was (not great), and a large set of the supernatural tricks. This was the template we initially used to make frost elves, as those E6 races were all buffed up to Pathfinder levels.
The other things were generally similar to 3rd- we just no longer were expected to believe that knowing longsword was similar to having wings or whatever.
The best thing about the Pathfinder system was how expressive the racial benefits and penalties were, IMO. They really showed how the averages were different, and how every single orc was stronger than whichever human matched up to them in the bell curve of strength, and dumber in the bell curve of intelligence. Really solid system.

In 5ed, we lose the racial penalty completely. This means that a lot of races will overlap. Generally, the rule for nonhuman races goes like this:
+2 to a physical stat, or very occasionally +1.
Subraces grant a further +1.
A pile of defining and powerful abilities and proficiencies. These are much more impactful than in previous versions, and this is absolutely the top strength of this system, where you can really define what it means to be a whatever.


The stats are the least important part. I'll list all the ones in the PHB so you can see how generally little variation there is here.
Elf: +2 Dex.
Subrace choice: High elf, Int +1. Wood elf, Wis +1. Dark Elf, Cha +1.
Halfling: +2 Dex.
Subrace choice: Lightfoot, Cha +1. Stout, Con +1.
Dragonborn: +2 Dex, +1 Cha.
Subrace choice: Determines color, damage, etc.
Gnome: +2 Int
Subrace choice: Forest, Dex +1. Rock, Con +1.
Half-Elf: +2 Cha
Bonus choice: Two other stats increase by 1.
Half-Orc: +2 Str, +1 Con
Tiefling: +2 Cha, +1 Int

Half-Elf is reasonably inexplicable: Only Dark Elves get any charisma bonus at all, and it's not +2. The "+1 to your second and third favorite stats" is taken from Variant Human (the most common human in 5ed, who gets to put +1 to two stats and start with a free feat- it's a generally top racial choice, compared to "standard human", which offers a +1 to every score and no one likes at all). Meanwhile, when the Orc stats came out, they didn't line up great with the Half-Orc stats either, as apparently Half-Orcs in particular are all about axes, with neither orcs nor humans sharing this strange hybrid obsession).

In any event, you can see that you have much less range to express a race, because you have no place to stick a fucking -2 on something that race is worse than mankind at, and you can't easily apply two +2s like you could in Pathfinder. If you have a +2 Dex and a +1 Cha, you could be a Dark Elf or a Lightfoot Halfling, and the Half-High-Elf-Half-Human would end up with +1 Dex and +2 Cha, which is very similar (and have one more +1). There's going to be bleed over here, is my point.

So the bulk of racial distinction lies in other powers.

Lets compare High Elves across additions as far as extra powers go. Here's 3ed:
1- Immune to Sleep spells.
This is powerful, flavorful, and good.
2- +2 to resist enchantment
This is interesting, but niche and will not matter. Unless the game world plausibly offers an immense amount of enchantments, you may go an entire campaign without this mattering.
3- Low Light Vision
This replaces infravision from 2ed, and is usually less powerful than it. The rules are hard to implement on the table, as a torch that casts light for 40 feet and dim light for 40 feet no longer does that, now JUST FOR THE ELF it casts light for 40 feet and dim light for 80 feet. It is still a good rule to have about how elves have great eyesight.
4- Longsword, rapier, longbow, shortbow
These end up helping your elf unless you are trash at using weapons or already good at these weapons, in which case, they do nothing at all.
5- Languages: You know elven, and any languages you have for being smart come from a list of Draconic, Gnoll, Gnome, Goblin, Orc, and Sylvan.
6- A +2 racial bonus on Listen, Search, and Spot checks. An elf who merely passes within 5 feet of a secret or concealed door is entitled to a Search check to notice it as if she were actively looking for it.

And Pathfinder:
1,2, and 3 are unchanged. 4 adds that you get to treat weapons with "elven" in their name as martial weapons, which means that they are free to come up with an exotic "elven" weapon that is slightly better, and an elven fighter will know that out of the gate. 5 adds Celestial to the list.
Then we have:
6- Turns into "the elf gets a +2 bonus on perception checks", losing the free search check. Pathfinder devs confirmed this was deliberate. Elf fans were outraged, but man it is nice not having to roll a million fake fucking dice as an elf player drags his token across the screen and asks.
This matters a lot, because perception replaced spot and listen, and is used for almost all encounters and when searching. Even though this is a +2, you will see this matter every couple sessions, and it feels great to have a +2 to it, even if your perception is otherwise poor.
7- The elf gets a +2 on caster level checks to overcome SR
This is meant, along with the +2 Int elves get in Pathfinder, to provide synergy for a wizard in the same way that getting access to elven martial weapons helps fighters, and access to longbows and longswords helps the simple-weapon physical crew. It's rarely impactful but it will matter if you play a wizard or sorceror at some point.
8- The elf gets a +2 on spellcraft to identify items
This is for flavor, and is even sparser on meaning than the +2 versus enchantment. You will go entire campaigns spamming elf bards and wizards before this matters even once.


Now 5ed:
1 and 2- Fey Ancestry: "You have advantage on on saving throws against being charmed, and magic can't put you to sleep"
"Advantage" means you roll twice and take the best, and it also means you can never be disadvantaged (at worst you make a raw roll). If anything ever tries to charm you, this will matter much more than the +2. Meanwhile, you retain your sleep immunity. This is, IMO, a much better way of handling this.
3- Darkvision: This means that within 60 feet of you, dim light counts as bright light, and darkness counts as dim light.
This means if you have a torch, the illuminate portions work correctly, and you just ignore certain penalties at certain ranges. This is a much improved thing.
4- These four weapon show up just for high elves and wood elves.
5- In this version it just adds elvish, and doesn't assume that elven schools offer electives in Gnome and Angel if you have a high enough int.
6- Keen Senses: You have proficiency in the Perception Skill.
This is a bigger deal than a +2 to perception, but doesn't help you be better than a human who worked at it in the way that +2 does. Proficiency starts at +2 and scales upwards at CEILING[level/4]+1, capping at +6. You may also have some way to turn this into something even better than proficiency, and if you were going to get perception from your class, you will pick a different skill instead. A non-elf who is picking a class and wants proficiency in perception will be just as good as the elf, however.
7 and 8 are pathfinder things that didn't make it to 5ed.
9- Trance: I always had this as a optional (maybe house?) rule, I believe it's from the elves in Forgotten Realms. This lets the elf not have to sleep.
10- High elves get a cantrip as if a wizard. Cantrips are legit (even moreso for casters), so this is a moderate deal. You can cast a cantrip every round, without limit, so you and your high elf lunch buddies at high elf high school can just spam message once a round, or that one psycho kid can do firebolt once a round for 1d10 damage at anything in 120 feet. Forever.

You can see how much more of the elven identity is contained in these special powers than before.


So when porting races, put more emphasis on the secondary abilities, keep them low in number, but make them impactful. That seems to be the 5ed design on them.