What are the earliest witnesses for the Christian cross with the different shapes

1. https://dzen.ru/a/ZXNFALUrMW9CfeYc https://www.pravenc.ru/text/2459015.html 2. I am not really sure if this is Christian. Some say it is. https://herculaneum.uk/Ins%205/Herculaneum%205%2015%20p4.htm 3. https://www.livescience.com/42761-ancient-church-mosaics-uncovered-israel.html 3. https://fr.wikipedia.org/wiki/Croix_(christianisme) 4. https://www.pravenc.ru/text/2459015.html 5. Why are there so many cross variants, and are there ancient writers that describes them? Why do we see so rare in the early time the standard latin cross without enlarged ends? But instead we see with enlarged ends. Thanks in advance.