I also tried one of these - https://www.amazon.co.uk/Sony-Playstation-handed-Dragon-cont... - but could never get the hang of it.
I might try this. My son is very into video games and I would love to play with him again. The only games that I played with him when he was younger were fighting games like Tekken and Soul Calibur and a few simple beat em up games but the games he plays now are too complicated to play with one hand.
EDIT:
I'm still trying to figure out after watching the videos, how this works with one hand. They showed a guy who had cerebral palsy that affected his right side but they never went into details about how he adapts it.
Maybe they were just expecting the target market to know about assistive technologies? I've never used any so I don't know anything about them.