From 1d4chan

The Fremlin, or Friendly Gremlin, is a foot-tall winged goblinoid creature, possessed of a powerful innate immunity to mundane weaponry. Whiny, lazy, gluttonous little trouble-makers, they are still better company than their relatives in Advanced Dungeons & Dragons, because at least they're not interested in hurting people. They do still love to play practical jokes, but they would never dream of injuring people the way their more malicious cousins would.

Fremlins have been known to "adopt" people they find nice and entertaining, but the relationship is usually one-sideed. Fremlins are of little use in combat, and in fact often end up making things worse for their allies by making "innocent" blunders that do things like give away hiding locations.

Easily insulted, despite or perhaps because they are so annoying and obnoxious, they will often disappear for a time, but their memories are fairly short-term and so inevitably they pop right back up again, usually when their former comrades were sure that they'd finally gotten rid of them for good.

Yes, you read all this right; fremlins are actually worse than kender. If Kender are those stupid kid sidekicks in 70s/80s cartoons, then Fremlins are the small annoying cute creature sidekicks in those self-same toons.

Horrifically, fremlins were actually presented as a PC race option in 2e's "Complete Book of Humanoids". Though the book noted that PC fremlins should be less annoying than the NPC ones, it also confessed that they're predominantly a comic relief race. Fortunately, unlike kender, they never caught on and so now nobody remembers the little shits.

Ability Score Range: Strength 2/11, Dexterity 8/18, Constitution 4/13, Intelligence 6/18, Wisdom 3/16, Charisma 3/18
Ability Score Modifiers: +2 Dexterity, +1 Intelligence, -3 Strength
Class & Level Limits: Wizard (Generalist or Illusionist only, 10), Thief (12)
Natural Armor Class 6
Can only by hurt by +1 or better weapons.
Can Fly with movement speed 12 and maneuverability class B.
Can only wield weapons scaled to their size, which thus do only 1/3rd of the normal damage.
Weapon Proficiencies: Dagger, Pixie Sword, Size-Scaled Weapon.
Nonweapon Proficiencies: Begging, Danger Sense, Drinking, Eating, Fortune Telling, Gaming, Hiding, Reading/Writing, Set Snares, Spellcraft.
Dungeons & Dragons 2nd Edition Races
Core: Dwarf - Elf - Gnome - Half-Elf - Half-Orc - Halfling - Human
Dark Sun: Aarakocra - Half-Giant - Mul - Pterran - Thri-kreen
Dragonlance: Draconian - Irda - Kender - Minotaur
Mystara: Aranea - Ee'ar - Enduk - Lizardfolk (Cayma - Gurrash - Shazak)
Lupin - Manscorpion - Phanaton - Rakasta - Tortle - Wallara
Oriental Adventures: Korobokuru - Hengeyokai - Spirit Folk
Planescape: Aasimar - Bariaur - Genasi - Githyanki - Githzerai - Modron - Tiefling
Spelljammer: Dracon - Giff - Grommam - Hadozee - Hurwaeti - Rastipede - Scro - Xixchil
Ravenloft: Broken One - Flesh Golem - Half-Vistani - Therianthrope
Book of X:
Alaghi - Beastman - Bugbear - Bullywug - Centaur - Duergar
Fremlin - Firbolg - Flind - Gnoll - Goblin - Half-Ogre - Hobgoblin
Kobold - Mongrelfolk - Ogre - Ogre Mage - Orc - Pixie
Satyr - Saurial - Svirfneblin - Swanmay - Voadkyn - Wemic
Dragon Magazine: Half-Dryad - Half-Satyr - Uldra - Xvart