Howdy all. I've been terribly inactive for the past week, so it's nice to come back to multiple pleasant surprises. I'm posting while waiting to get my coiffure busted, so this will be short for now.
Bronzong + Recover Is very nice: a simple buff can go a long way and defensive Steels are generally hard-pressed to stay healthy. Bronzong has already proven useful against most fairies but easily overwhelmed with repeated attacks. I like this one a lot; there's not much to be said about it that hasn't already been covered. I guess it would be possible to pull off a stupid CM set now with its immunity to Toxic and Psyshock to go "mixed", but that's probably better left for Reuniclus. I can see (utility move) + Recover + 2 Attacks working out pretty well. If you're into durable weather setters, you could use Recover + Rain Dance with a Damp Rock, although I'm not sure how well that would work out given that you can already rain+explosion. Very good submission.
Mandibuzz + Delta Stream sounds pretty neat but would be incredibly difficult to deal with outside of M-Gardevoir, Sylveon, etc. Delta Stream solves a lot of the defensive typing problems associated with Mandy's Flying type. D-Stream Mandibuzz is much easier to pair with mons that formerly shared weaknesses like Talonflame, M-Pinsir, Starmie, M-Venusaur, Slowbro &c . It takes a lot of pressure off of other members of balance/defensive cores.
Thundurus-Therian + Competitive you know that part of the sound of music where the nuns are all like "what are we going to do with julie andrews?" Thundy-T is kind of like that, and the buff from Competitive is a very good place to start. The main selling point is Intimidate / Defog abuse, so if the need for a volt-turner overlaps with a need to punish Defog / Intimidate, it's really quite good. My problem is that it's hard to tell how decent of a niche that is.
Mega-Beedrill -> Bug/Ground is a really thoughtful offensive buff, and I'm having a hard time choosing between it and Bronzong. The loss of fairy-killing prowess blows, but the unique typing inb4 nincada is great. The electric immunity is great, and adaptability makes drill run quite powerful.