I firstly want to say that most of the team styles that were relavent in reg M-A are still at least somewhat relavent in Reg M-B with the exception being rain which has changed a ton since Reg M-A. I’m not going to talk about those team styles in this answer because they are quite rare but if you want to read about them read this
Common team Archetypes
Staraptor teams
Despite tons of counters arising Staraptor teams are still one of the most common teams you will face as you journey the M-B ladder. There are also 2 kinds of Staraptor teams. Staraptor teams that are centered around mega Staraptor and have Pokemon like Whimsicott and Grimsnarl that can support mega staraptor as it sets up close combat boosts. The other kind of teams are team that have staraptor as a second mega for taking on teams that lack a good mega Staraptor answer. Keep in mind that the latter kind of team sometimes run final gambit staraptor and if you don’t keep that in mind you can get seriously messed up by a final gambit sniping one of your teams important Pokemon. These teams typically include support Pokemon that can help keep staraptor alive and Pokemon that can remove ghost types that staraptor cant hit with Cc. The best counter to mega Staraptor is by far Ghouldengo as Ghouldengo isn’t scared of staraptors stabs and fits on most teams quite well. Froslass and Raichu Y are also good choices but they require you to mega them in order to deal with Staraptor.
Mega Raichu Y teams
The next most common mega is Mega Raichu Y. These teams typically lead Raichu plus a support Pokemon and have Raichu fake out the fist turn while the support Pokemon sets something like light screen or tailwind up. After that they tend o try to position Raichu with other attackers to pressure both your opponents Pokemon at once so they’re forced to switch and potentially paralyzed as they try to get into a better position. Mega Raichu is typically not seem as a standalone mega on a team and is either pared with Staraptor or swampert. The best Teamates for Raichu are things that can help it avoid dammage (again because of its toothpick bulk) and Teamates that can deal with ground types. (Thats part of why it synergies with rain teams so well). Good counters for it include Sinitcha who Raichu can’t hurt and non mega Raichu.
Rain teams
Rain teams are probably the most difficult team to play into in the current meta just because there are so many things that can go wrong when you’re playing into them. Pelliper can mess up you game plan with tailwind and Arch can because a serious problem if you lacks special attacker or strong physical attacker to remove it. The trickiest thing about playing into rain teams is just how much dammage all of the Pokemon can do and the fact that all the Pokemon on rain teams cover each others weaknesses really well. Rain teams often include the core of Arch, Pelliper, M-Swampert and sometimes Sinitcha which gives them amazing offenceive and defensive coverage. Unfortunately there isn’t one easy way to deal with rain teams in general the best you can do is try to force them to play defensively so they waste their rain/tailwind turns. Running sunny day on one of your fast and frail support Pokemon can be a big help If you want a more deticated rain counter.
Pyroar teams
Pyroar teams are centered around mega Pyroar and sun. Generally they have Pyroar and whimsicott but outside of those 2 the other Pokemon on the team vary greatly. They are worth being aware of however because sunny day from whimsicott plus heat wave from Pyroar can literally cook un prepared teams. The best ways to deal with these teams is to use a Pokemon Pyroar cant one shot but can one shot Pyroar. Like Garchomp for example. Keep in mind that outspeeding Pyroar typically won’t work as mega Pyroar is insanely fast and whimsicott typically runs tailwind to support it.
Trick room teams
There teams are basically the same as they were in Reg M-A except they now have mega Mawile as an option. If you want to read more about trick room teams go to the trick room part of this answer
If anyone thinks there is a relevant team type I’m missing please leave a comment and I’ll add it
