Breloom is overrated and not broken at all. Spore is annoying, I get it, but its not different from Sleep Powder or Lovely Kiss except for the accuracy. Of course, Breloom is strong by itself even without Spore, so he is a different threat compared to something like Tangrowth. This means you have to both absorb the Spore and resist Breloom Moves to be a reliable check.
Its time to show a list of shit I consider viable that check Breloom well. I will divide them in 2 parts:
1. Checks that deal very well with every Breloom that doesn,t have Rock Tomb. I am yet to see a Rock Tomb Breloom in this Meta, but the move is good and viable in order to invalidate some checks. Still, more often than not, you will see Breloom without Rock Tomb, since to use it, it has to give up either Spore or Sword Dance (Band Breloom probably is the best set with Rock Tomb):
-Dragonite. Resists both STABs, can have Roost, can kill Breloom with multiple things. Defensive Dragonite is probably the best at this.
-Gengar. Immune to one STAB, resists the other. Easily takes 3 Bullet Seeds of LO Breloom and up to 5 from LO one. The best thing is that Bullet Seed has more chances to trigger Cursed Body.
-Latios. Again, not the best check and defintely don,t absorb Spore with this one unless its Specs + Sleep Talk. Still, works after something else absorbs Spore.
-Togekiss. Now, this one laughs at every move except Rock Tomb. It also OHKOs Breloom and is bulky enough to actually wake up, so its a good Spore absorber.
-Arcanine. Defensive Arcanine can take everything except LO/Band Rock Tomb and absorbs sleep well. Its not a Mon only to use for Breloom, since it checks Weavile, Scizor, Jirachi and Infernape too, among others. Has niche in Stall teams.
-Ariados. Now, I will admit this one is exclusively for Breloom. Its immune to Spore thanks to Insomnia and resists x4 both STABs. Despite being literally only for Breloom, its the only Sticky Webber in the game that can lead against the mushroom. It also gets Toxic Spikes as additional bonus.
-Charizard. Viable in Sun teams. Its spamming Fire Moves and Focus Blasts, so it has room to run Sleep Talk as last move.
-Drifblim. If burned (Flare Boost), it absorbs any Breloom move and can throw powerful Shadow Balls that will deal heavy damage to everything that is not Blissey or a Dark Type.
-Heracross. Guts (Flame Orb or Band Sleep Talk) wallbreaker. Lives any 2 hits from Breloom and OHKOs back.
-Moltres. Takes both STABs easily. I have actually used this Mon and as punishment to Scizor (a very common Mon) with Flame Body, its very good. It gets Defog (though it can,t be the only Defogger of the team) and can Defog away Rocks from Clefable, Gliscor and Hippowdon, among others. Hits hard with Flamethrower and Hurricane (except when there are Blissey, Heatran, Tyranitar or Rotom).
-Salamence. Dragonite but with Intimidate instead of Multiscale. This goes for both Defensive and Offensive sets.
-Shedinja. Everyone knows what this does at this point. Well, Rock Tomb-less Breloom is one of the victims.
-Torkoal. Bulky enough to absorb Spore. Can also use Restalk reliably.
-Tropius. Harvest is fun. Need Spikes to work, but I have used this Mon to get reqs for Latios. Works as Subseeder with Harvest + Sitrus Berry. With the support of hazards, can dismantle some teams in a epic way.
-Venomoth. Dangerous Quiver Dance Mon that resists x4 both STABs.
-Vespiquen. Haven,t tried this yet, but outside of Aerodactyl, this is the only Deffoger that has Pressure. It beats these Rockers:</p><p>Clefable: 0 SpA Clefable Flamethrower vs. 252 HP / 252+ SpD Vespiquen: 90-106 (26.1 - 30.8%) -- guaranteed 4HKO < Only can win with CM.
Empoleon: 252+ SpA Empoleon Ice Beam vs. 252 HP / 252+ SpD Vespiquen: 138-164 (40.1 - 47.6%) -- guaranteed 3HKO < Normally Empoleon will be defensive, but Vespiquen can beat even offensive variants if there are no crits.
Defensive Garchomps that don,t have SE.
Gliscor without Taunt.
And Blissey unless lots of parahax.
On top of that, it beats non Rock Tomb Breloom and switches into Tangrowth, which is relevant for Specs variants.
-Victreebel. Sun Mon immune to Spore.
-Xatu. Magic Bouncer. Never liked this Mon, but many people consider it viable. At least it does wall Breloom.
-Yanmega. Terrific wallbreaker. Has room to run Sleep Talk as 4th move, since only special STABs and U-Turn are really needed. Rock TOmb-less Breloom is a free switch-in for Yanmega and very few things actually switch into Yanmega after that.
-Zapdos. Why is this bird not OU? Well, this time I don,t need to prove that its viable.
2. Mons that check Breloom even if it has Rock Tomb.
-Gliscor. Not very good to switch into Bullet Seed, but handles every other move. Facade usually 2HKOs.
-Latias. This goes in this section, unlike Latios. Way bulkier and can run defensive sets. Deals very well with Breloom due to being bulky enough to wake up.
-Tangrowth. Totally walls Breloom and kills with Sludge Bomb. Only Sub-Punch Breloom can be a threat, and very minuscule one.
-Sip Sapper Azumarill. Unfortunately, it lost Whirpool, so Breloom is really the only reason to run. Lets go to the next check.
-Cresselia. Bulky enough to wake up and KO with Psychic.
-Exeggutor. Again, Harvest is fun. Its worse that Tropius, but has niche in TR teams. Totally walls Breloom and OHKOs.
-Roserade. Has a niche as Spiker and can be a Pdef one to check both Breloom and the more dangerous Azumarill. Also Clefs without Flamethrower.
-Venusaur. Sun sweeper, bulkier than Victreebel.
-Vileplume. Bulky but slow Grass. Totally destriys Breloom.
-Weezing. Neutralizing Gas makes Poison Heal Breloom die and the Technician one very weak. Its bulky enough to wake up.
Even though most of these Mons are not common, there are enough Mons that are OU by usage alone that deal with Breloom well enough. I say this as someone that both used and faced Breloom lots of times. Also, I haven,t even mentioned yet about Breloom's inhability to come safely into the field and numerous weaknesses that allow for easy revenge killing.
