I recently visited Munich and was able to purchase a Bayern card, which allowed inexpensive travel within Bavaria and into Salzburg. The card cost 59 euros for 4 adults and was good for the day to travel back and forth to any destination. I was wondering if there is something similar in London/England?
Not generally, but there are Rail Rovers and Rangers for various areas of the Country- https://www.railrover.org/
Cornwall for instance has the Ride Cornwall ticket which covers all buses and trains within the County for £18 for a day. The Lake District has the Lakes Day Ranger- all trains, buses and Windermere boats for £29.90 or £58.80 for a family.
Wales has a whole range of tickets which cover buses and trains.
Very many urban areas (like York, Edinburgh and Glasgow as a few examples) have something called Plus Bus- https://www.plusbus.info/
This is a day bus rover ticket for all operators in that particular urban area issued in conjunction with a train ticket to that town/city. That is almost always a very good deal indeed.
In Greater Manchester and Derbyshire there is the Greater Manchester Wayfarer- all trains and buses in a very large area across the two counties.
And Merseyside has the Saveaway Ticket- all trains and buses across Liverpool, Merseyside and the Wirral (and trains only cross boundary on to Chester)- very good value.
Northern Ireland has the ICard.
It is all a bit of a patchwork around the UK.
...and of course the daily cap for London Tube/bus/etc. It's just that you don't pay for it up front, but the net result is the same.