1. I have three favorite foods: pizza, coffee, and ice cream.

2. I have three favorite foods, that is to say, pizza, coffee, and ice cream.
3. I have three favorite foods, viz. pizza, coffee, and ice cream.
4. I have three favorite foods, viz., pizza, coffee, and ice cream.
5. I have three favorite foods, viz pizza, coffee, and ice cream.
6. I have three favorite foods, viz, pizza, coffee, and ice cream.
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Which ones are the same as #1? Let me clarify the use of punctuations here.
Thank you.

They all mean the same. The colon should be used in all of them, with or without "viz." (viz.: pizza...). "I have three favorite foods, viz.: pizza,..." viz. is not necessary, though.