These are all the links used in the 2021 Bracket Matrix.
Tier 1 (3+ years in the matrix, above average)
The Bracket Project
The 17th Seed
Bazinga Bracketology
Boiling the Bracket
Bracketball
Bracketology Corral - Bill Riccette
Bracket Bros
The Bracket Mensa
Brackonomics
Bracksketblogs
Bucky's Bracket
Busting Bracketologists - CJ
Drew's Bracketology
Graham Doeren Bracketology
Head vs. Gut
Heat Check CBB
Hoops HD - Jon Teitel
Inside the Hall
Ivar's Blog
Jabesblog
Jason Wells' Bracketology
KY Brackets
Kyle Foster's Bracketology
MAG
Making the Madness
March Madness 2021
M+J's Bracket Watch
Mind of Mike Broman
Mondays are for Bracketology
No Perfect Bracket
Nothing but Nylon
Oak Creek's March Madness
Prime Time Bracketology - Grant Hansell
Random Bracket Blog
Razorbrackets
RFS Bracket Science
RSN Bracketology
Selje's Bracketology
Stuck in 1977
Syracusefan7's Bracketology
WNUR Sports
Bracket Forecast - Rusty Tutton
Bracket WAG
Busting the Bracket - Jeff Borzello
The Catch and Shoot
CBS Sports - Jerry Palm
D Ratings
Delphi Bracketology
Elam Seeding Predictions (M-Sports Fans)
ESPN - Joe Lunardi
Facts and Bracks
Lobofan2003's Bracketology
One Man Committee
Pulse on Sports - Kevin Pulsifer
RaleighWX Bracketology
Rocco Miller's Bracketology
RotoWire BracketZology - Adam Zdroik
Ruckles Bracketology
SB Nation - Chris Dobbertean
Tier 2 (1-2 years in the matrix, above average)
Bauertology
Bracket Beyond
Crazy Sports Dude
From the Rafters
Full Court Press
Hardwood and Hollywood
TheNightVenom
Seanny P Bracketology
seeding68
Sluder Bracketology
The Truth's Bracketology
Anthony's Blog
Bracketometry
Cardinaldave's Bracketology
Connor Groel's Bracketology (Top Level Sports)
Devils Digest - Jeff Griffith (Formerly Sideline Intel)
DPI Bracketology
The Game Haus
Isaac Perrigo's Bracketology
NCAA.com - Andy Katz
Robo Macketology
Ryan Tures Bracketology
The Stats Guru
Tier 3 (3+ years in the matrix, below average)
Aidan's Bracketology
Beef's Bracketology
Blacketology
Bracket Predictions
Bracketville USA
Bracks on Bracks
Brad-ketology
Carolina Sports Thoughts
Deuce 2 Sports
Eye on the Tournament
G Money's Sports Page
HoopsHD
Tier 4 (1-2 years in the matrix, below average)
The BIG Heartland Bracketology (formerly JGood)
BracketBot
Bracket Prophet
Bracket Racket
Bracketology Busters
Busted Bracketology
CBB Review
Cracked Sidewalks
Heartbreak City
Let Me B-Frank
Logan's Sports Ratings
Made for March
The Pi-Rate Ratings
Bracket Bingo
Crossroads Sports
Deceptive Speed
The Geek's Bracketology
INCC Stats
Radio.com - Jordan Schwartz
Recspecs730 - Luke Benz (formerly YUSAG)
Sportemind Bracketology
Streaking the Lawn
Tier 5 (New to the matrix)
Jacob Larson's Bracketology
Last Word on Pro Basketball
Mad About March
Mark Stouffer's Bracketology
MRFSF68