Hello.
So I found out that The Dude package is not supported on RouterOS anymore. Is there are any way to monitor other subnets?
Sorry for my dumb questions, i’m newbie. Also sorry for my bad English. 
The Dude uses SNMP (mainly) to probe the devices that you have configured for monitoring. The protocols that are used by The Dude are all supported byTCP/IP (in my experience anyway) and, so are rotable. Therefore Dude can monitor devices on any subnet so long as there is a route to that subnet from your Dude server. Perhaps I do not understand your question properly? Can you post a specific example of what the issue is?
For example, I’m (Dude server) on subnet 192.168.2.0, but i need to monitor also subnet’s 192.168.3.0 devices behind NAT. With The Dude agent on Router OS i could do this, but it isn’t supported now.
OK - a NAT setup. Not a situation I have in my system. I can see why you need a Dude agent to monitor remote subnets. Windows Dude server can also act as an agent, but could be costly in licensing of Windows servers and hardware as well. Sorry - no simple answers from me.
I have multiple subnets in different networks interconnected by l2tp tunnels. Devices are monitored directly without any problem with one dude only. I am not using nat, just pure routing between the networks.