Acme Products - The series is set in Acme Acres and Acme products are very common.
Alliterative Name - Bugs, Buster and Babs Bunny (no relation), Daffy Duck, Porky and Petunia Pig, Wakko Warner, the Road Runner, Calamity Coyote, Pepé Le Pew, Penelope Pussycat, Fifi La Fume, Henery Hawk, Cool Cat, Claude Cat, Slappy and Skippy Squirrel, Beaky Buzzard, Dizzy Devil, Pete Puma, Minerva Mink, etc.
And Call Him "George"! - Elmyra Duff is an example of that. And don't forget the trope namer Hugo the Abominable Snowman.
Anvil on Head - Various skits feature this classic gag.
Animation Bump - The first and second seasons, followed by the fourth season, share animation with Tiny Toons Adventures and Animaniacs, as well as the early 2000s webtoons.
Art Evolution - The first and second had an animation style similar to Tiny Toons Adventures and Animaniacs, but the third season had episodes resorted to a downgrading quality (possibly due to the production of Looney Tunes: Back in Action 2). After its release, the fourth season returned to the first and second seasons' animation style.
Aww, Look! They Really Do Love Each Other - In some episodes, Sylvester really cares about Tweety and sees him like a younger brother. The same happens with their Tiny Toon Adventures counterparts. And there's also the moments that Penelope actually has feelings for Pepé.
Badass Bookworm - Wile E. Coyote (and by extension, Calamity Coyote), self-proclaimed super genius.
Belligerent Sexual Tension - While Bugs and Lola (and by extension, Buster and Babs) seems to be the perfect couple, the same we can't say of Daffy and Tina (and by extension, Plucky and Shirley) and in a minor extent, Porky and Petunia, since there's various moments they argue with each other. Despite not being de facto a couple, there's a lot of this between Pepé and Penelope.
Beta Couple - Sylvester/Sylvia to Tweety/Aoogah.
Big "SHUT UP!" - In Foghorn Leghorn's words, Ahhh, shut up!
Biting-the-Hand Humor - Various skits constantly mock Warner Bros., Cartoon Network and WB Kids.
Breaking the Fourth Wall - Various characters (mainly Bugs Bunny, Daffy Duck, Elmer Fudd, Foghorn Leghorn and the Warner Siblings) commonly do that.
Butt Monkey - Almost everyone suffrered from it, even the ones who commonly win.
Carnivore Confusion - Foghorn Leghorn suggested to the Barnyard Dawg to find chicken at a fast-food chain in one episode.
Catchphrase - Most of the cast has one.
Christmas Episode - Every season has one.
Crossdresser - Very common, specially when we talk about Bugs Bunny (and occasionally Daffy Duck).
Darker and Edgier - The Halloween episodes.
Densier and Wackier - Compared to various Looney Tunes television adaptions.
Disney Owns This Trope - Apparently, the Acme Corporation owns almost everything in the series. It's even hinted in a few episodes that the Acme Corporation also owns Time Warner.
Disneyfication - Most of the stories intended for adult audiences are spoofed in that way in the series.
Distaff Counterpart - Most of the female characters fit on this.
Do Not Call Me "Paul" - Bugs Bunny when Cecil Turtle mistakes his name, Lola Bunny when she's called "doll", Babs Bunny when she's called by her full name and Dot Warner when she's called "Dottie".
Dogged Nice Guy/Girl - Pepé Le Pew (and by extension, Fifi La Fume) and the Warner Siblings.
Double Entendre - Despite being a family-friendly show, various skits use this trope.
Early Installment Weirdness - In A Special Kitty, Penelope Pussycat was mentioned as Sylvester's sister, but in latter appearances, they're refered as cousins.
Expy - The Tiny Toons to the Looney Tunes.
Fat Bastard - Thaddeus Plotz, naturally.
Five-Man Band - Bugs Bunny (The Leader), Daffy Duck (The Lancer), Porky Pig (The Smart Guy), Sylvester (Team Pet) and Tweety (Tagalong Kid). Occasionally, Foghorn Leghorn serves as the Sixth Ranger.
Funny Animal - Obviously the animal cast.
Funny Foreigner - Speedy Gonzales, Slowpoke Rodriguez, Pepé Le Pew (and by extension, Fifi La Fume) and Dr. Otto Scratchansniff.
Genki Girl - Babs Bunny, Dot Warner and Elmyra Duff.
Getting Crap Past the Radar - Despite its TV-Y7-FV rating, the series features a lot of adult subtlety.
Girly Pigtails - Petunia Pig (like usual).
Halloween Episode - There's one in every season.
Half-Dressed Cartoon Animal - The most notable examples are Porky Pig (Hamton J. Pig is debatable, since he uses overalls), Buster Bunny, Plucky Duck, Shirley the Loon, the Warner Siblings and Slappy Squirrel.
Hello, Nurse! - Not exactly unexpected, specially when one of the characters is commonly called by that name.
Heterosexual Life Partners - Bugs Bunny and Daffy Duck or Daffy Duck and Porky Pig, Hubie and Bertie, Mac and Tosh Gopher (despite hinted to be siblings), Babbit and Catstello and Pinky and the Brain.
Hypocritical Humor - Apparently, Daffy Duck has a certain dislike of Sylvester due to his speech impediment.
I Am Not Weasel - Hippety Hopper (always confused with a mouse), Penelope Pussycat, Furrball (sometimes confused with skunks) and the Goofy Gophers (confused with squirrels, mice and hamsters).
Interspecies Romance - Technically, Shirley the Loon isn't a duck. Don't forget Yakko and Wakko Warner's crush on Hello Nurse. Also if you count Pepé Le Pew and Penelope Pussycat's on/off relationship.
Jerkass - Daffy Duck (and by extension, Plucky Duck).
Junior Counterparts - Once again, the Tiny Toons to the Looney Tunes. Also Clyde Bunny to his uncle Bugs Bunny and Sylvester Junior to his father Sylvester.
Karmic Trickster - The Bunnies and sometimes the Ducks. Also the Birds and the Warner Siblings.
Large Ham - Yosemite Sam, Foghorn Leghorn and Wile E. Coyote at their best. Occasionally also Daffy Duck.
Limited Animation - It pretty much became that after the second season (mostly copying DePatie-Freleng's 60s' style of animation) and was later averted in the fourth season.
Loads and Loads of Characters - Merging four shows into one is an example of that.
Logo Joke - Porky Pig saying Th-th-th-that's all, folks! in the Warner Bros. Animation shield.
Man/Woman of a Thousand Voices - The majority of the male cast in almost all episodes. On the female side, we have Kath Soucie, Grey DeLisle, Tress MacNeille and Tara Strong.
Motor Mouth - Foghorn Leghorn and Sniffles.
Outlaw Couple - Bunny and Claude.
Rascally Rabbit - The Bunnies, obviously.
Returning the Roots - Used once in one of Wakko Warner's lines from The Warners and Mr. Jones, where Wakko's voice returned to its Animaniacs Season 1 voice for only a short time.
Role Reprisal - Most of the cast reprise their roles from former incarnations.
Screwy Squirrel - Bugs Bunny, (sometimes) Daffy Duck (and by extension, their female and Tiny Toon Adventures counterparts), Foghorn Leghorn and Slappy Squirrel.
Self Deprecation - Similarly to its predecessors, the series loves to take shots at itself, the writing team and even the animation studios.
Shout-Out - Like its predecessors, it has a lot of pop culture references to classic and current-day media and celebrities.
Species Surname - Almost all the animal characters.
Stalker with a Crush - Once again, Pepé Le Pew (and by extension, Fifi La Fume).
Suddenly Voiced - Hector the Bulldog, Calamity Coyote, Marc Anthony and Pussyfoot. Wile E. Coyote, Penelope Pussycat and Furrball are exceptions, since the first speaks in some media (most of them without the Road Runner), the second spoke for the first time in Really Scent and Carrotblanca and the third had a few (but short) times that he actually spoke.
Take That! - Disney, Viacom and Fox are common targets.
Talking to Himself - Jeff Bergman does a lot of this when he's both Bugs Bunny and Daffy Duck and both Sylvester and Tweety. In the Dodgers Team segments, is also obvious with Jeff Bergman voicing both Daffy Duck and Plucky Duck and Bob Bergen voicing both Porky Pig and Marvin the Martian, besides also voicing both Hubie and Bertie in their segments. Rob Paulsen, being Yakko Warner, Pinky and Dr. Otto Scratchansniff, also fits on this. It's also common with Grey DeLisle, but not too much with Kath Soucie and Tress MacNeille.
The Cameo - Mainly from other Warner Bros. characters.
The Other Darrin - More obvious with the Looney Tunes characters, where the male voice actors are completely this to either Mel Blanc or Stan Freberg.
The Verse - It's hinted in several episodes that the main Warner Bros. animated media (Looney Tunes, Tom and Jerry/Droopy, Hanna-Barbera, Collin the Speedy Boy and The Doggies) share the same universe.
Unpopular Popular Characters - Not counting with Elmyra Duff, it seems that no one likes Pinky and the Brain. However, they remain one of the most popular characters in the franchise.
Vitriolic Best Buds - Bugs Bunny and Daffy Duck (and by extension, Buster and Babs Bunny and Plucky Duck). In the first case, they're always depicted as best friends, but they have their conflicts sometimes. The second case is an inversion of their Looney Tunes counterparts relationship, since they're commonly bickering with each other. There's also the case of Foghorn Leghorn and the Barnyard Dawg and some situations where Sylvester Pussycat and Tweety Bird are actually friends.