Your ability score rolls are modified as follows:

Your Sprite and Fey nature gives you an affinity for observation and remaining hidden, you have proficiency with Perception and Stealth, you are also proficient with Herbalist Kits and can use them to make poisons.

At DM discretion you may be able to scrounge enough components to make Sprite sleep poison. Each use of a herbalist kit to make this poison creates enough venom to coat 10 sprite sized arrows or 1 medium creature sized arrow. Anyone hit by one of these poisoned arrows must make a DC10 Constitution saving throw or become Poisoned for 1 minute. If its saving throw result is 5 or lower, the Poisoned target falls Unconscious for the same Duration or until it takes damage or another creature takes an action to shake it awake.

Your Fey heritage enables you to be able to read, speak and write Common, Elf and Sylvan.

As a Sprite you have two special abilities: Heart Sight & Invisibility.

Heart Sight: If you touch a creature you can use your Action to discern the creatures emotional state in terms of happy, sad, manic, etc and can force the target to make a Charisma Saving Throw. If the target fails the saving throw, you also discern the creature's alignment. Celestials, fiends, and undead automatically fail the saving throw. The DC for this saving throw is equal to 8+ your proficiency modifier + your Cha bonus.

Invisibility: Your Fey nature enables you to be more stealthy. You can attempt to hide even when you are only lightly obscured by foliage, heavy rain, falling snow, mist, and other natural phenomena. When you are in a lightly obscured area, you can use your Action to become invisible, this lasts until you  move or until you take and Action, Bonus Action or Reaction. Additionally, you can use an Action to become Invisible as per the spell, you can do this a number of times per long rest equal to your Charisma Modifier (min 1).

You are proficient with the Sprite Longsword and Sprite Bow. Regardless of the weapon proficiencies you may gain from class levels, the biggest non-Sprite weapon you can use is a dagger and this must be used two handed, any other weapon is simply to big for you to wield effectively.

The Spite Longsword deal ONE point of slashing damage but has the finesse property and the Sprite Bow deals ONE point of Piercing damage and has range increments of 40/160. The arrows you shoot are about 4 inches long and look like thin thorns. If you have proficiency with Fletchers tools you can make more arrows (using a survival or nature check to locate suitable thorny plant life and a successful tool check to make the arrows).

Due to your size you cannot wear any armour that is not specifically made to fit you, normally only Sprites or Pixies would manufacture such small clothing and armour and most medium sized creatures would be unlikely to be able to produce effective armour in such a tiny style. However, you are deemed to have a suit of Sprite Leather Armour at time of character creation. This armour grants you AC 11 + Dex modifier. Regardless of the armour proficiencies you gain you are unable to use a shield as a Sprite sized shield would be ineffectual against normal sized weapons..

The combined weight of these weapons, 20 arrows and armour is 2lbs.

Due to the Sprites size certain class abilities may change and players would be encouraged to fully think through any class or spell options and highlight any thing that may need to change to their DM, but some things to consider would be:

Abilities such as Sneak Attack and Critical hits may not deal as much damage as they normally would as your size and weapons do not offer as much damage potential.

Other abilities or spells may also change, Enlarge/Reduce for instance will increase your size to Small or reduce it to Diminutive.

General stuff, trinkets and Spell Components! You are a tiny Sprite, you have no carrying capacity, if you are a spell caster what are you going to do with all those spell components? What about if you like to hoard things? A Bag of Holding is larger and weighs more than you do, normal component pouches are big enough for you to use as a make shift sleeping bag and an arcane spell focus may well be unwieldable and as for carrying around that red dragons scale to cast Aganazzar's Scorcher or diamond to cast Chromatic Orb....well...you might need some good, and slightly larger, friends to do the carrying for you.

Magic Items in general: a lot of magic items may well be beyond your ability to use, scrolls will likely be as long as you are tall and weapons and armour will be too heavy for you to lift.

On the bonus side, some things may be a positive change, being tiny makes it much easier to find 1/2 or 3/4 cover and makes you harder to spot at a distance let alone hit at a distance.