Your .Find is obviously the Range.Find method because it contains arguments that aren't present in the WorksheetFunction.Find method.
The Range.Find method requires an expression that evaluates to a Range Object.
ThisWorkbook.Sheets("Sheet2").column(1)
doesn't evaluate to a range. You can test this by entering in the Immediate pane
ThisWorkbook.Sheets("Sheet2").column(1).select
which will return an error 438
Object doesn't support this method or property
whereas
ThisWorkbook.Sheets("Sheet2").Range("A:A").select
works just fine in the Immediate pane so replace ThisWorkbook.Sheets("Sheet2").Column(1) with ThisWorkbook.Sheets("Sheet2").Range("A:A")
The return from a Range.Find method is a range so the variable that takes the return should be defined as a range
Dim rng as Range
If you don't have Option Explicit at the top of your module, all variables are assumed by VBA to be of Variant Type but the Variant Type is not interchangeable with Object Types.
If you set your VBA IDE to always "Require variable declaration" via Tools > Options > Editor Tab Option Explicit will be added to every module in your projects and you will not suffer from incorrect variable calls.
Now Objects can't be assigned by using ObjectName = .... They must be Set using Set ObjectName = ... and the return must be of the same type as the object being set.
If you Dim rng as Range then the method on the right side of the Set rng = ... must return an object of the same type or an error will occur.
Your What:=Accessibility, is trying to find the contents of a variable named Accessibility which probably doesn't exist. Find the string "Accesibility" will work even if it's embedded within other characters if you LookAt:=xlPart.
To summarise:
Define your object Dim rng as Range
and change your line
rng = ThisWorkbook.Sheets("Sheet2").Column(1).Find(What:=Accessibility, _
LookIn:=x1Values, LookAt:=x1Whole, MatchCase:=True)
to:
With ThisWorkbook.Sheets("Sheet2").Range("A:A")
Set rng = .Find(what:="Accessibility, LookIn:=xlValues, LookAt:=xlPart)
End With
which should leave you with a rng.value that you can use.