Letter Sets

Inspired by both the List of Things and a puzzle I wrote last year, this is a list of sets of letters. Entries in brackets are considered semi-canonical; they exist in some lists but aren't definitively in the set.

Sets of Three

RGB - Light colours

XYZ - Cartesian axes

TMO - Dash only Morse code

BLT - Sandwich

AZE - Isotope notation

Sets of Four

NESW - Cardinal directions

UDLR - Orthogonal directions

AJQK - Playing cards

CMYK - Printer inks

SATB - Voice types

ACGT - DNA nucleobases

ACGU - RNA nucleobases

WASD - Keyboard movement

ABXY - Xbox controller buttons

HJKL - Vim navigation buttons

EISH - Dot only Morse code

Sets of Five

RNBQK (+P) - Chess pieces

ACGTU - Nucleobases

PRNDL (+SB) - Automatic gearstick

LITSO - Free tetrominoes

AEIOU (+Y) - Vowels

GJPQY - Descenders (lower case)

ABCDF - US Letter grades

DRABC - First Aid primary survey

LGBTQ (+IA) - 🏳️‍🌈

Sets of Six

UDSCTB - Quark flavours

UDLRFB - Faces of a Rubik's Cube

PEMDAS/BODMAS/BIDMAS/BEDMAS - Order of operations

Sets of Seven

ROYGBIV - Colours of the rainbow

IVXLCDM - Roman numerals

ABCDEFG - Western music scale

IOTJLSZ - Fixed tetrominoes

OBAFGKM - Main stellar classifications

ZXCVBNM - Keyboard bottom row

PYFGCRL - Dvorak top row

BDFHKLT - Ascenders (lower case)

HINOSXZ - Capital letters with rotational symmetry

Sets of Eight

BCDEGPTV (+Z) - Rhymes with "-ee"

Sets of Nine

ASDFGHJKL - Keyboard home row

QJKXBMWVZ - Dvorak bottom row

BCDEHIKOX - Capital letters with horizontal symmetry

Sets of Ten

QWERTYUIOP - Keyboard top row

AOEUIDHTNS - Dvorak home row

NUBTQPHSOE - Systematic element name symbols

Sets of Eleven

AHIMOTUVWXY - Capital letters with vertical symmetry

Sets of Twelve

FILNPTUVWXYZ - Pentominoes

AEHIKLMNOPUW (+') - Hawaiian alphabet

BCFHJLPQVXYZ - Four-symbol Morse code

Sets of Fourteen

HBCNOFPSKVYIWU - Single letter elements

OBAFGKMLTYDCS - Extended stellar classification

ABEZHIKMNOPTYX  - Greek capital letters

Sets of Twenty

ACDEFGHIKLMNPQRSTVWY (+OU) - Amino acids

Sets of Twenty-Six

ABCDEFGHIJKLMNOPQRSTUVWXYZ - English alphabet