It's looks like a Toto Ultimate, MS854114 from some years ago.
Lowes Hardware will sell a replacement fill valve, the Korky Quietfill, and the repair part for it.
and the blue 3" flappers when you need a replacement.
Any standard side mount trip lever should work for it, I believe the Eljer might work there.
The book price on a chrome THU004#CP Toto lever is $23.00