What are all of the road blocking Pokemon?

Question

What are all of the Pokemon that block you from going further unless you use a specific item on them.(Snorlax, sudowoodo, psyduck. etc.)

Comments

The Hoenn games have Kecleon.

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There are a lot in the Alola games that don't require an item to be used on them, but instead they don't move until you beat a trial or something

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In Galar on Rt. 8, a Crustle appears in the northwest, blocking the narrow path leading to TM43. It does not respawn.
https://bulbapedia.bulbagarden.net/wiki/Galar_Route_8#Wanderers

Also, in LGPE, two Snorlax block the road on Rt. 12 and 16 respectively.

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Oh, I remember the Crustke, but I don’t think it counts

Answer 1

Here's all of the blocking Pokemon that I can think of:
-Snorlax in the Kanto games
-Sudowoodo in Johto blocking Ecruteak City until you get the Sprinkling Bottle from the Flower Girl in NE Goldenrod City post-Whitney
((Maybe you would count Ampharos in Olivine City until you get the SecretPotion from the Cianwood City Pharmacy post-Chuck))
-Kecleon in Fortree City until after you talk to Steven and battle/catch the Kecleon on Route 120 and get the Devon Scope
-Psyduck in Sinnoh's Route 210 until you get the SecretMedicine from Cynthia after beating the fleeing Team Galactic Grunt post-Crasher Wake
-Crustle that Colress clears on Route 4 in Black/White 2 which you need to save the stolen Pokemon from Team Plasma post- Burgh
-Snorlax again in Kalos on the bridge on Route 7 until you retrieve the Poke Flute from Parfum Palace

I have a feeling I'm forgetting some, but that's all of them that come to mind

Answer 2

Gen 1 - snorlax
Gen 2 - sudowoodo
Gen 3 - kecleon
Gen 4 - psyduck
Gen 5 - crustle
Gen 6 - snorlax (again)
Gen 7 - trial/totem technically
Gen 8 - wooloo
Gen 9 - the Pokemon in the bluberry dlc you fight before terapagos
(glimmora/ gargarnacl/ noivern)