Function BinarySearch(AString : String; Data: array of string) : integer; // -1 if not found, else the index in "Data" for which AString = Data[Index].

(I'll assume you can either code a binary search, or use another option if a binary search isn't possible for whatever reason)

For I := 0 to (InputFile.LineCount - 1) do
begin
  Index := BinarySearch(LeftStr(InputFile.Lines[I], Pos(',', InputFile.Lines[I], My_List_Of_Every_Preset)));  
  If Index != -1 then begin
  SetPresetDamagePointsForPrefixByName(My_List_Of_Every_Preset[Index], StrToFloat(RightStr(InputFile.Lines[Index],  Length(InputFiles.Lines) - Pos(',', InputFile.Lines[Index]))); // I think I got the brackets right
  end
end else Continue;