I've got left handers in my family, including a grandfather who was forced to write with his right hand.
I am classed as mixed handed. I'm not truly ambidextrous, as that is when you can do everything with both hands, but I can write with both hands. There are some things I do left handed and some things I do right handed, with my right hand being the very slightly more dominant hand.
It's weird stuff, though, eg, I can't whisk with the right hand.
My mother could also write with both hands, but in her case, it was because she broke her right arm a couple of times as a kid, and the school insisted she still complete her schoolwork, so she had to learn to write left handed.
Neither DC is left handed, but I was prepared in case they were. I think the best left handed stuff I had was information on writing left handed, to avoid that cramped hook hand style. Which boils down to tilting your paper, in some cases quite a lot. I know a left hander who basically tilts her paper at nearly 90 degrees, writing down the page, effectively. She reckons it stops her wrist aching.