In Mikrotik we can create the null route for IPv4 and IPv6 as well, just add a route like this:
IPv4 Null Route Creation Example.
/int bridge add name=Null0
/ip add =10.10.10.1/24 int=Null0
/ip route add dst=192.168.1.0/24 type=blackhole
IPv6 Null Routing Creation Example.
For IPv6 all are same but you have to use type=unreachable to configure the blackhole this effect for IPv6.
NO blackhole option is available in IPv6.