Supporting feats for EDs and ED level monsters that I'm aware of:
*Kushala Daora dispelling a snowstorm by flapping its wings in a 4U cutscene (6-C).
*Hellblade Glavenus stated in lore to be able to vaporize a mountain in one attack in both Gens and MHSt2 (6-C).
*Ceadeus sinking an island in the lore with a tsunami in MHtri (Anyway between Low 7-B to 6-C depending on the timeframe and size of the island).
*Rusted Kushala summons a massive storm in a 4U cutscene (needs to be calced but will likely be 7-B upto 6-C).
*Velkhana was stated to be capable of freezing the Ancient Rainforest by a NPC in Iceborne (Likely 6-C but dodgy since it's a temperature feat).
Teostra stated in lore to be able to turn a desert into glass in both MHDos and Frontiers iirc (Against depends on the timeframe and size of a desert but ofc it's a temperature feat, so it might not even be useable).
*Kirin and other EDs passively change the weather in each ecosystem in the New World (7-A was the result for Coral Highland iirc).
*Ceadeus shaking Moga Island by scratching it's horns against the side of it in a MHtri cutscene (Likely a 8-A to 7-C feat since Moga isn't a large island iirc).
*Gore Magala can darken the skies of an entire ecosystem with the black eclipse (likely 7-A however there are some scaling issues).
*And there's
this (Can this even be calced?).
Overall the scaling is a follows:
Dangerous First Class Monsters (5-A scaling to White Fatalis pseudo-black hole, moving the moon and the several world destroying statements all those monsters have) > Major ED tier (6-B to High 6-A scaling to Zorah nuking the New World continent, Dalamadur's world shaking/burning statements and the implications of Shara Ishvalda replicating Zorahs feat or something similar) > ED tier (Scaling to 6-C via the above mentioned bullet points with Kushala Daora being the baseline) >>> Apex tier (Essentially any monster that's a non-ED tier flagship or can match blows with Lagiacrus and other Apexes, scaling to upper High 8-C) > Mid tier (mid game monsters that can put up a decent fight but hard lose to any Apex, scaling to Barroth in lower High 8-C) > low tier (early game monsters that are usually the punching bags, most notably the bird wyvern dromes scaling to 8-C via downscaling from Barroth) > jobber tier (all small monsters that are 9-B simply due to most of them being comparable if not superior to IRL animals).
Thoughts?