There is the history and logbook views, which are both pretty useful for viewing state changes over time, but neither of these states display the actual yaml value of the state.
For example the sun.sun entity will display when it is "Above horizon" or "Below horizon", but the actual states possible are above_horizon and below_horizon. I can see the current yaml state and attributes in the developer tools view, but I would love to be able to see past states as well, so that I can use them when creating automations, scripts, etc.
In the case of sun.sun, I just looked at the documentation but for less well documented entities it can be a real struggle to find the possible state values.