When a college football team is thriving, that success is always a product of multiple position groups playing well. But one particular unit usually deserves much of the praise.

In the early stages of the 2020 season, several of these units have emerged. For this piece, "best" describes the most effective position groups on the most successful teams. So, yes, the highest-ranked programs are well represented.

Additionally, the selections provide a snapshot of what has happened so far, not necessarily a projection of what's to come.

Quarterbacks are not included in the list; only positions with two-plus contributors were considered.

Appalachian State Secondary

Two years ago, Appalachian State showcased an overwhelming secondary. That team surrendered 5.7 yards per pass attempt and a 56.5 completion percentage and logged 17 interceptions to eight touchdowns. This season's secondary is statistically comparable.

So far, the Mountaineers have surrendered just 491 passing yards in three games. Opponents have completed an FBS-worst 40.5 percent of their attempts with a meager 6.6 yards per throw.

Shemar Jean-Charles leads App State with eight pass breakups, while Kaiden Smith has four and an interception. Shaun Jolly is a terrific corner, and Ryan Huff (pictured) has an interception too. That quartet is the foundation of a lockdown secondary.

BYU Running Backs

While quarterback Zach Wilson is the star and the offensive line deserves a ton of credit, BYU's running backs are excelling too.

Tyler Allgeier (pictured) has scampered for 391 yards at a scorching 7.4-yard clip and scored four touchdowns in four games. Lopini Katoa has provided versatility with 215 rushing yards and eight catches for 78 yards, totaling four touchdowns.

For good measure, Jackson McChesney added 56 yards and a score before a season-ending foot injury.

Wilson will—understandably—grab headlines if the Cougars keep winning games, but the rushing attack has been a significant part of BYU's 4-0 start.

Cincinnati Secondary

One important caveat is Cincinnati's competition. Austin Peay is an FCS program, and Army is reliant on the running game. But the Bearcats dominated both of them and shut down South Florida.

The secondary has ceded just 5.1 yards per attempt, a 51.5 completion percentage and only 515 passing yards. Three players—star corner Ahmad Gardner (pictured, 12), Arquon Bush and Coby Bryant (pictured, 7)—have nabbed two interceptions apiece, while Gardner and safety James Wiggins each have three pass breakups.

Cincinnati entered 2020 with high expectations for the defensive backfield, and the unit is exceeding them.

Oklahoma State Linebackers

You are reading this correctly: In a program known for its offense, the linebackers are Oklahoma State's strength.

Running backs Chuba Hubbard, LD Brown and Dezmon Jackson merit shoutouts, but Amen Ogbongbemiga (pictured), Malcolm Rodriguez, Calvin Bundage and Devin Harper have demanded the spotlight.

Ogbongbemiga leads OSU with 22 tackles, and the other three are within the top five. Bundage boasts a team-best five tackles for loss and 3.5 sacks, while Rodriguez checks in with four tackles for loss. Ogbongbemiga and Harper have 1.5 and two stops in the backfield.

They've helped the Pokes rank sixth nationally in yards per carry allowed and tackles for loss per game. And, most importantly, Oklahoma State has surrendered just 27 points in three games.

Georgia Linebackers

Georgia has incredible linebacker depth, versatility and production. And as starter Monty Rice succinctly said, per Jed May of the Macon Telegraph, "Nobody in our room sucks."

Rice is the cornerstone of the unit in the middle, and he's collected a team-high 18 tackles in three games. Next to him is sophomore Nakobe Dean, a rising star who has 15 tackles and is dangerous in coverage and as a blitzer.

Azeez Ojulari and Adam Anderson are disruptive off the edge; they've combined for five sacks and 15 hurries. Rice, Channing Tindall and Nolan Smith each have at least 1.5 tackles for loss. As if that's not enough, Quay Walker has 12 stops and three hurries.

Nobody in the room sucks. That's a massive reason why the Bulldogs have ceded a devastatingly low 3.7 yards per snap, which leads the nation among teams that have played more than one game.

Notre Dame Offensive Line

After the Fighting Irish rushed for 353 yards in a victory over Florida State, quarterback Ian Book praised the guys up front.

"I feel like we have the best O-line in the country," the graduate student quarterback said, per Patrick Engel of Rivals.

It's difficult to argue otherwise. Notre Dame has piled up 812 yards and 12 scores on the ground in three games, generating a terrific 6.3 yards per carry. The blocking unit has allowed only three sacks and nine negative plays in 206 snaps.

From left tackle to right tackle, it's Liam Eichenberg, Aaron Banks, Jarrett Patterson, Tommy Kraemer and Robert Hainsey.

Pitt (Oct. 24) and Clemson (Nov. 7) have disruptive front sevens, but the offensive line is built to handle those challenges.

Clemson Defensive Line

What's new, right? Clemson constantly signs top-ranked defensive linemen, so it's no surprise the unit is excelling.

The ridiculous part, though, is how many young players are contributing. Freshman end Myles Murphy has a team-high six tackles for loss, while sophomore ends Justin Mascoll and K.J. Henry (pictured, 5) have combined for 3.5 sacks. Freshman tackle Bryan Bresee has 1.5 sacks and two pass breakups, and freshman tackle DeMonte Capehart has two tackles for loss.

And that doesn't even include sophomore tackle Tyler Davis (pictured, 13), who returned to action after two games out as junior end Xavier Thomas made his season debut Saturday. Additionally, two graduate students—end Regan Upshaw and tackle Nyles Pinckney—have combined for 20 stops with 4.5 tackles for loss.

Clemson ranks seventh nationally in tackles for loss per game and eighth in yards allowed per carry.

Alabama Wide Receivers

Alabama has exactly three wide receivers with a catch, so it's reasonable to question the unit's depth. But all three are producing at least 99.3 yards per game, so it's not a critical problem.

John Metchie III (pictured) is two yards short of a 100-yards-per-game average. The sophomore has piled up 298 yards and two touchdowns on just 11 catches, giving the Crimson Tide a sensational third option behind their stars.

DeVonta Smith—a second-team Associated Press All-American last year—is the leading target with 27 catches for 316 yards and two scores. Jaylen Waddle offers a blend of volume and explosiveness, pulling in 19 passes for 396 yards and three touchdowns.

Good luck stopping this trio.

All recruiting information via 247Sports. Stats from NCAA.com, cfbstats.com or B/R research. Follow Bleacher Report college football writer David Kenyon on Twitter @Kenyon19_BR.