In no particular order:
The 43rd Antarean Dynasty
Aliens Love Oranges
Squonk the Apprentice
Now +n, Now -n
The Trouble With Death Traps
The Great Old Pumpkin
Friction
Tk'tk'tk
What are the images that bring up those episodes?
The architecture, with the spiral ramp to heaven, and the temples big enough for God to fit in.
The bar scenes, with people talking about how to recognise an alien.
Squonk making a wizard's hat for himself.
Business meetings with your future self.
The arguments over traps to include.
The Cththulu Pumpkin itself.
The great desert, made up of worn-away corpses.
The distinctly alien attitudes towards hospitality and business.