Ik a lot of these were already mentioned but I wanted to add to them.
[name_m]John[/name_m]- [name_m]Ivan[/name_m], [name_f]Ivanka[/name_f], [name_f]Ivana[/name_f], [name_f]Jean[/name_f], [name_f]Jane[/name_f], [name_f]Jeanette[/name_f], [name_f]Joan[/name_f]
To explain [name_m]Charles[/name_m] to [name_f]Caroline[/name_f], Charles–>Carl–>Carol–>Caroline
Elizabeth-Isabelle was most surprising out of all the variants in the group. I believe the original name was Elishava/Elishaba. The [name_f]El[/name_f] then got dropped off and a lot of romance languages apparently didn’t like ending on a t sound from what I’ve read so it became Isabel/Isabelle in a lot of the romance languages. Others that makes sense in hindsight but probably not known to the common layperson are [name_f]Lisa[/name_f], [name_f]Elsa[/name_f], [name_f]Elise[/name_f], [name_f]Eliza[/name_f], [name_f]Isa[/name_f]
[name_f]Catherine[/name_f] =Karen, [name_f]Catalina[/name_f], [name_f]Katerina[/name_f], [name_f]Katya[/name_f], [name_f]Katrina[/name_f], [name_f]Caitlin[/name_f], [name_f]Kathleen[/name_f], [name_f]Karina[/name_f]
Alice/Adelaide-also [name_f]Alison[/name_f], [name_f]Adeline[/name_f], [name_f]Alisha[/name_f], [name_f]Alicia[/name_f], [name_f]Alyssa[/name_f]
William=Guillaume and [name_m]Guillermo[/name_m]
[name_m]Stephen[/name_m] & Estaban
[name_m]Sandy[/name_m] from [name_f]Alexandra[/name_f]