It started with Yochanan (Hebrew) -> Ioannis (Greek) -> Johannes (Mediaeval Latin) -> Jon (Middle English), but now every language seems to have a version, e.g.

• Hans
• Joanna
• Hanna
• Jan
• Ivan/Ivanka
• Vanja
• Jens
• Sean/Shaun/Shawn/Shane
• Joan/Jane/Jean/Janis
• Evan/Ewan
• Jock/Jack
• Ian/Iain/Ianto
• Juan
• Yiannis/Gianna
• Gianni/Giovanni/Vanni/Giovanna
• Jonas
• Ivo/Iva
• Eoin/Owen
• Seonaid/Siubhan

and those are just the ones I’ve heard used, there are hundreds more!