I've previously riffed on "my elves and dwarves". Translating this over to mechanics, tho, makes me a little uneasy.

I've got a bit of a bug in my bonnet over people attaching too much "inherent flavor" to mechanics. For example, in my current D&D game I'm playing a Bard. The other players in my game have tried to refer to me as such in-game, and I had to correct them - my character isn't a bard by any stretch of the imagination. He's a noble son, raised in the Mondavi family tradition, which involves a mix of physical, social, and magic training, and uses a musical/lyrical focus for their magic to double-dip on those categories. There's no "Bard's College" that he's associated with, and he doesn't play music in taverns for coin or tell stories to crowds (tho he can certainly tickle the ivory in a more upscale party, if he wants to entertain his friends).

I spread this same philosophy to all the classes in the game, tho it does sometimes require one to be a little creative in interpreting things. The point is just that mechanics are nothing more than numbers and rules; they can admit a lot of interpretations, and doing so frees up character-gen in a lot of interesting ways.

I think the same should apply to races. I don't necessarily want to RP as a half-orc just because I want a tough person who's great with big weapons; maybe I just want my character to be a human, or a buff elf. And, overall, this actually works quite well - with a little bit of creative tweaking, all the "races" in the DMG can be interpreted as just traits you're born with / trained into earlier in life, before you started adventuring. Reusing the terminology from some other games, they become a "Background Feat" granted at first level. This has precedent in several systems I'm already familiar with: Iron Heroes had some feats marked as "Background Feats" which could only be taken at first level, and were a little more powerful than a normal feat; Numenera's character creation consists of completing the phrase "I'm an ADJ NOUN who VERBS", where the NOUN is your class and the ADJ and VERB are additional qualities that can represent your upbringing or race.

The only exceptions to this are the handful of "flavor" features that are definitely more biological, not thematic. The half-orc's traits suggest Strong but they also have darkvision, not because they're strong but because that's how half-orcs work. Same for elf trance, or halfling/gnome smallness. These carry little to no mechanical value - they're not used to balance the races - so it's okay to just attach these to the race itself, rather than the trait we extract from them.

So, here's the D&D 5e races, reinterpreted as background qualities that can apply to any race:

Tough

• Con +2
• Adv on saving throws against poison
• Resistance to poison damage

and one of:

• Wis +1, HP +1/hit die
• Str +2, proficient in light/med armor

Fae-Blooded

• Dex +2
• Proficiency with Perception
• Adv on saving throws against charm

and one of:

• Int +1, cantrip, extra language
• Wis +1, speed 35, hide when lightly obscured
• Cha +1, learn dancing lights, faerie fire (at 3rd level), darkness (at 5th level)

Wily

• Dex +2
• Reroll 1s on attack/damage/skill/saving throw, must take second result
• Advantage on saving throws against frightened
• Move thru space of equal or larger creatures

and one of:

• Cha +1, can Hide behind an equal or larger creature
• Con +1, advantage on saving throws against poison, resistance to poison damage

Skilled

• +1 to all stats, or
• +1 to two stats, proficiency in one skill, gain one feat

Elemental

• Str +2, Cha +1
• Magic blast (5'x30' line or 15' cone, choose acid, lightning, fire, poison, or cold), 1/rest
• Resistance to your blast element

Smart

• Int +2
• Advantage on Int/Wis/Cha saving throws against magic

and one of:

• Dex +1, gain minor illusion cantrip, simple talking with small animals
• Con +1, Expertise in Int(History) checks about magic/alchemical/tech items, tinker to create small devices

Charming

• Cha +2, +1 to two other stats
• Advantage on saving throws against charm
• Proficient in two skills

Fierce

• Str +2, Con +1
• Proficient in Intimidate
• Can drop to 1hp instead of 0, 1/rest
• +1 die on crits

Demon-blooded

• Cha +2, Int +1
• Resistance to fire damage
• Know thaumaturgy, hellish rebuke (at 3rd level), and darkness (at 5th level), usable 1/day

Angel-blooded

• Cha +2
• Resistance to radiant and necrotic damage
• Can touch a target to heal HP up to your level, 1/day
• Know *light*
• At 3rd level, can transform for 1min (or until you end it as a bonus action) 1/day. During transformation, can deal extra radiant or necrotic damage (choose at char creation) equal to level to one attack or spell per round. Extra transformation details in each subrace.

and one of:

• Wis +1, fly speed 30' while transformed
• Con +1, while transformed shed bright light 10' and at end of each turn everyone in 10' (including you) take radiant or necrotic damage equal to half level
• Str +1, when you transform creatures in 10' must save (DC 8+Cha+Prof) or be frightened until end of your next turn

Forest-touched

• Wis+2, Str+1
• Know detect magic, disguise self, usable 1/rest
• Bonus action to turn invisible 1/day, ends at start of next turn, or when you do something hostile
• Beasts and plants can understand your speech. Advantage on Cha checks to influence them.

Strong

• Str +2, Con +1
• Proficient in Athletics
• Can use reaction to reduce damage by 1d12+Con, 1/rest
• Can carry as if a size larger (double weight)

Imitator

• Dex +2, Wis +1
• Adv on checks to make forgeries or produce duplicates of existing objects
• Proficient in 2 of: Acrobatics, Deception, Stealth, Sleight of Hand
• Can mimic voices, Insight vs Deception to tell your voice is an imitation

Raised in the Wild

• Con +2, Wis +1
• Can harvest creature Small or larger to make shield, club, javelin, or 1d4 darts or blowgun needles, during short rest
• Hold breath for 15min
• Proficient with 2 of: Animal Handling, Nature, Perception, Stealth, Survival
• AC = 13 + Dex
• Bonus action for unarmed strike; on hit, you gain temp HP equal to Con. Usable 1/rest

Agile

• Dex +2, Cha +1
• Can Dash as a free action. Can't do this again until you move 0ft during a turn.
• Climbing speed 20'
• Proficient in Perception and Stealth

Amphibious

• Str +1, Con +1, Cha +1
• Can breath water and air
• Know fog cloud, gust of wind (at 3rd level), and wall of water (at 5th level), usable 1/day
• Water-breathing animals can understand your speech.
• Resistance to Cold, ignore drawbacks of underwater environment