So I've been looking into possible lower tier threats that may excel specifically under trick room, and I believe that I've found an interesting (though potentially outclassed) contender.
Camerupt@Life Orb
trait: solid rock
4hp/252atk/252spatk
Quiet Nature
-fire blast/overheat
-Earthquake/Earth power
-Stone edge
-hidden power [grass]/[ice]
A lot of pokemon from generation 3 were incredibly lackluster, mostly due to their stat distribution. Most offensive pokemon are either slow but powerful and bulky, or frail but powerful and fast. Most generation 3 pokemon however were offensive in nature yet slow as well as frail, as they were mixed attackers. Yet because of their low BSTs their offences themselves were hardly usable since their base stats were split between two stats. I feel no gen 3 pokemon better illustrates that then Camerupt.
This Camerupt set however allows the volcano camel to utilize both his offences to their full potential while also circumventing his awful speed. With 252 EVs in both offences he becomes a mixed attacker stronger than most OU mixed pokemon, as they often run 252 EVs in speed and split the remaining 256 between their offences. Camerupt has fantastic STABs, and also two coverage moves that gel wonderfully with them. The reason I looked to Camerupt was because trick room often gets the drop on HO teams, but struggle with stall teams. most trick room sweepers run choice items because trick room turns are far too limited to allow for boosting. This makes them easily outplayed or outpredicted by stall, and without boosting they often lack the raw power to break through walls, while HO teams crumble because of their relative frailty. Camerupt changes this, as he has fantastic mixed attacking power and coverage, and speed low enough that he can outspeed almost all offensive pokemon in trick room and also possesses the coverage and wallbreaking ability to cause stall teams major problems.
hidden power grass is for quagsire who is a common staple of stall teams, however hp ice can be used for dragonite and garchomp, or flash cannon can be used for fairies (keep in mind though OU's most popular fairy is Azumarill so you're probably better with hp grass anyway, and even then you can only hit Azu on the switch since it has 4x effectiveness STAB priority). Stone Edge can be foregone for hp rock/ancient power if you're using flash cannon and earth power and you want to use a bulky fully special attacker spread, but the power drop is obvious and you also lose out on Camerupt's great mixed attacking wallbreaking. Eruption is an option, however it will require both a defogger or spinner and not using life orb to allow Camerupt to be at full health, the only time it outpowers the other listed fire moves. On top of this an expert belt full health Eruption = 180 bp, while a life orb overheat = 182 bp and a life orb fire blast = 156 bp, making it hardly ever worth it. You could use choice specs for an astonishing 225bp eruption and still no hp drop, but if you're using specs eruption in trick room simply use Heatran since Camerupt's niche is his coverage and mixed stats.
In complete honesty Camerupt probably isn't worth using, His offences are just a bit too low and being simultaneously frail and slow is a death sentence and he lacks a really exploitable ability. I just wanted to throw this out there in case anyone was looking for answers to stall for trick room.