Crosswords

Smaller:
The Atlantic
Vulture 10x10
Vox
Washington Post Mini

Easy:
USA Today Easy
Sheffer Crossword

Medium:
USA Today
Universal
USA Today Hard
USA Today Stan's
Thomas Joseph

Big/Sunday:
USA Today Sunday
Evan Birnholz
Merl Reagle
Premier Sunday
New York Magazine

Hard:
Washington Post/L.A. Times
New York Times note: The Seattle Times puzzles are delayed from the true NYTimes puzzles by about a month
New Yorker
Wall Street Journal

Indies:
7x Words see also Girlbosswords/Malaika Handa
Adam Aaronson
AlphaBento Crosswords/Lawrence Denes
Amanda Rafkin
Arctan(x)words/Christopher Adams
Bewilderingly/Will Nediger
Brendan Emmett Quigley
Chris Piuma
Cross Angel Mind Freak
Crosswords From Outer Space
Cross Hare can make your own too!
Cruciverbalista
Crosswords With a Kick/Jay Low Jay has an even more thorough list here
Cruzzles/Ricky Cruz
Datalexic/Enrique Henestroza Anguiano
Donkey Puzzle Tree
Et Tu, Etui/Darian Wellop
Generalisms and a handy difficulty matrix
Glutton For Pun/Erik Agard
Grids By Gubin/Brian Gubin
Grid Pro Quo/David Harris
Grids These Days / Paolo Pasco
Happy Little Puzzles/Matthew Stock
Half-Baked Puzzles/Will Eisenberg
Island of Misfit Puzzles
Jack of All Squares
Jonesin'
Just Gridding
crosswords schmosswords/kateschmate
Lexicon Devil/Richard Allen
Luckystreak Xwords/Adam Nicolle
Matthew Luter Crosswords
Max Puzzles
M & M Crosswords
Norah Sharpe Puzzles
Patrick's Puzzles
Pun of a Kind
Puzzles That Need a Home
Puzzle Jag
Puzzles by Quin
Queer Qrosswords
QVX Crosswords/Quiara Vasquez
Rossword Puzzles/Ross Trudeau
Sid's Grids/Sid Sivakumar
Ryan Fitzgerald
Tough as Nails/Stella Zawistowski
Trash Panda Puzzles/Jac Crabtree
Words Xing
XWords By a Ladee/Brooke Husic
XXXWordInfo saucy xwords.

Paid/Subscription Based:
Crucinova
Inkubator crosswords by ladies!
Grids for Good
Luckystreak+
American Values Club
Fireball Crosswords
Newsday

Competitions:
American Crossword Puzzle Tournament
Boswords
Lollapuzzooola

Other Crosswords:
Provincetown Independent no app
100 Year Anniversary Google Doodle
Muller Monthly Music Meta
Spyscape Crosswords

Miscellaneous Crossword-Related Things:
How to Solve a Crossword Puzzle
Construction Advice
Crossword Fiend
Rex Parker Does the NYTimes Crossword Puzzle
Sally's Take on the USA Today Crossword
XWord Info