this is highly regional..
so basic on line info is just general in nature and should not be relied on in any fashion.
title search will handle most of the easement and encumbrances of record issues.
really depends on if your buying land that has ALL public services.
or is it in the boonies. ?
so once you describe in a little detail what your trying to buy and WHERE it is maybe local folks can chim in on what you should be looking for.
but a good start is always at the county.
1. planning department make sure it zoned for what you want to do.
2. public works make sure you have or what the utls situation is.
3. Tax assessor you can glean general info there.
If it is in New York, you will want to be on the look out for abbandoned underground fuel oil tanks.