So I've typed up in Excel all the First Grade and Kindergarten benchmarks from the book by Rebecca Rupp called "Home Learning Year by Year". Benchmarks are things a typical school kid "needs to know." But you be the judge of that.
Obviously, some stuff like knowing the alphabet and basic math is important and leads to learning. There are other things on this list that you might just say, "sure, but we can hit that hard later on." And you would be fine. If you are teaching one child right now, it will be no problem to hit all these points. If you are like me and teaching 3 older kids and thinking about doing kindergarten with a 5.5-year-old soon while wrangling a younger one, you might choose to put some first grade things off (like surveying Ancient Greece) while focusing on things like telling time and spelling.
Other grades can be found under the Blog Category of Benchmarks, as well as by grade.
Here are the benchmarks for First Grade. As I'm putting them into Excel and uploading them to Google Docs, the spreadsheet doesn't split into sheets there, so you have to just scroll from Kindergarten on down. I'll be adding the others as fast as my fingers can type!
I suggest buying the book so you can also benefit from all the wonderful resources the author provides, as well as a longer description of each benchmark.