I never liked much full Trick Room teams, because as Lee said, they lack tactical flexibility and diversity. However, Trick Room cores can be pretty effective, as long as you don't have more than one Pokemon that is defined by Trick Room. For example, a pretty effective core that i used in 5th gen was OTR Reuniclus and 4 Attacks Sheer Force Conkeldurr with LO. While Conkeldurr may be slower than almost everything, its great bulk and access to priority make him able to be useful with or without TR up.
Another example is Trick Room Focus Sash Alakazam. This Pokemon typically plays as a revenge killer and cleaner, but should the opportunity arise, Alakazam can take any single hit (except from multi-hit moves) and set up Trick Room, allowing you to deal with the threatening sweeper with your slow mons and simultaneously putting you on the counter-offensive.
From the new Pokemon and the old ones that received significant buffs, here are some that strike me as good Pokemon both inside and outside of Trick Room, and could be paired effectively with dedicated Trick Room sweepers such as Reuniclus, Slowing, or Slowbro:
Mega Ampharos
Great bulk, great resistances, dgaf about Talonflame, slow, powerful, with access to Volt Switch. What's not to love? While this guy may be too slow to be a consistently great choice in OU, this problem can be mitigated to a degree by using him in combination with a single Trick Room Pokemon.
Mega Abomasnow
While i haven't used at all the frosty try this gen, i am hearing very good words about it. Most notably, his great wallbreaking power, bulk, and access to priority, could make him good in and outside of Trick Room. I could be wrong though, as this is complete theorymon.
Mega Mawile
Do i really need to explain this one? Mega Mawile is an offensive juggernaut and a very viable choice even outside of Trick Room, where it's only means of mitigating its low Speed is the unreliable Sucker Punch. Imagine what it can do under Trick Room... And it also resists a lot of common priority moves (Brave Bird, Ice Shard, Sucker Punch, Extremespeed), is weak to none, has great physical bulk to take priority, and even has access to its own priority to outrun opposing priority users under Trick Room. Oh, and it resists Dark, one of the most common and troubling weaknesses of most Trick Room users. Easily one of the best Pokemon to pair with Trick Room users.
Crawdaunt
A simple 3 attacks + SD set can wipe out an offensive team all on its own under Trick Room, while having Aqua Jet to OHKO Talonflame before it tries anything smart, and resisting the other common priority moves, such as Sucker Punch, Shadow Sneak, Aqua Jet, and Bullet Punch. Against balanced teams, Crawdaunt can just maul through their defensive core without Trick Room up, so that your Trick Room user can clean up the remains. Against stall teams, Crawdaunt can set up SD and bring the pain. Another excellent Pokemon to pair with Trick Room users.
The furthest i would go in using a TR core on my team would be: OTR cleaner + Focus Sash Alakazam with Trick Room + Slow powerhouse that can function outside of TR too (Mega Mawile, Crawdaunt, etc). The OTR cleaner plays the role of the late game cleaner, Alakazam the role of the revenge killer, and the bulky powerhouse plays the role of the wallbrekaer, just like a regular offensive team would look like. This way, you can rip the benefits of Trick Room without suffering most of its drawbacks (bad against stall, lack of tactical versatility, problems with setting up SR).