The traditional name for the league is the Isthmian League - with a Premier Division, a Division One South and a Division One North. When sponsors started coming in in the 80s/90s, the leagues changed their names, hence the sponsors are Ryman at the moment. (I prefer the original league name - when I update the honours on my DHFC flag, I'm not gonna call it the Ryman League!)
There's some great and very random league names around - I remember the "Beazer Homes League Midland Division" which Forest Green Rovers used to play in when I was a kid. The Northern Premier League is now called the Evo-Stick League. I also like the Cherry Red Records League which covers Surrey/London - do they have great tunes at the grounds?!