If you want to go check out the rules and changes made for sixteen team regionals, you can see them here.

Austin Regional (Austin,TX)
1.Texas
New Mexico State
LSU
UCLA

Palo Alto Regional (Palo Alto,CA)
16.Stanford
Weber State
Denver
Northern Cal

Auburn Regional (Auburn,AL)
8.Auburn
Alabama State
AGCU
Duke

The Beach Regional (The Beach,FL)
9.Naples
Jacksonville
Florida
Florida Atlantic

Los Angeles Regional (Los Angeles,CA)
4.USC
UC-Irvine
Gonzaga
BYU

Tuscaloosa Regional (Tuscaloosa,AL)
13.Alabama
UNC-Asheville
Atlanta
Georgia Southern

Ft. Myer’s Regional (Ft. Myer’s,FL)
5.FGCU
Savannah State
Wake Forest
Florida International

Athens Regional (Athens,GA)
12.Georgia
Georgia State
Georgia Baptist
Virginia Tech

Little Rock Regional (Little Rock,AR)
3.Little Rock
Central Arkansas
TCU
Mississippi State

Raleigh Regional (Raleigh,NC)
14.NC State
UMBC
Michigan
St. John’s

East Lansing Regional (East Lansing,MI)
6.Michigan State
Delaware
SLM
Oregon

Norfolk Regional (Norfolk,VA)
11.Virginia State
VCU
Syracuse
Yale

Fayetteville Regional (Fayetteville,AR)
7.Arkansas
Southeastern Missouri State
Arkansas State
Northern Arkansas

Columbia Regional (Columbia,MO)
10.Missouri
Wichita State
Kansas
Notre Dame

Chapel Hill Regional (Chapel Hill,NC)
2.North Carolina
High Point
Northwestern
Harvard

Dayton Regional (Dayton,OH)
15.Dayton
Iona
Ohio State
Louisville