There is a very quick and easy way that lets ping a wide range of IPs to find out which IPs are free and which ones have been taken, using the PowerShell built-in cmdlet Test-Connection.

Try the PowerShell code below.
$iprange = 200..254
Foreach ($ip in $iprange)
{
$computer = "192.168.105.$ip"
$status = Test-Connection $computer -count 1 -Quiet
if (!$status)
{
$computer + " - available"
}
}