This is all speculation about the next raid rotation.
New Bosses:
T1
Metang
Shelgon
T2
Muk (return)
Pinsir
Flaaffy
Magcargo
T3
Ursaring
Forretress
T4
Armaldo
Venusaur (Return)
Flygon
Dragonite
Houndoom
Ludicolo
T5(Next Legendaries)
Latios
Latias
Regirock
Regice
Registeel
T5(EX)
Deoxys
Quest Rewards:
Mew
Celebi
Jirachi
Zapdos
Articuno
Moltres
Some things I changed in this if I was Niantic:
Shelgon as A tier 2 boss or probably not as a boss, the same with Metang. New tier one Bosses could be Beldum or Trapinch but I’m sure that won’t happen.
Ludicolo as tier 3 boss.
Dragonite probably won’t happen, but I like it.
Houndoom and Forretress as tier 2 bosses like they did with Exeggutor.
More quest reward Pokémon, as confirmed.
And maybe Armaldo too at tier 3
Since the raid bosses are centered around the weaknesses of Lugia, I assume the same would be for those that will come
So for regis, Breloom, Haryiama, Metang, Rhydon, Flareon
For Latis, Houndoom, Shiftry, Pinsir, Scyther, Shelgon
T1 has for several months been pretty consistent in having pokemon that were restricted to the water biome. So it wouldn’t amaze me at all if either Wailmer or Magikarp got replaced with Sharpedo, Lanturn or Whiscash. Maybe also Snorunt with Spheal, but I don’t really expect that one.
Simple reasoning behind this: Water Biomes are slightly less accessible to many players, so having two water-types is necessary to compensate and give people controlled access to those pokemon.
Of the weathertypes, ice is the least common for many players, so that gets some standard compensation through a T1 raidboss slot as well.
I would personally like to see more level 3 raids than this but it looks like a pretty good list. Maybe armaldo/ houndoom go to 3.
They definitely wouldn’t put Bagon or Beldum (or their evolutions) in raids. They’re the top tier of gen 3 so they won’t want to make candies easier to find in my opinion.
Dragonite would be great news, as they go with the surprises of heracross and tauros in Europe would be a great surprise