Today I'll start building a plugin for Unbound additional features, bringing DNSBL to @opnsense without the need for BIND or dnscrypt-proxy. Future versions will offer DoT and more (depending on your ideas)
For manual black and whitelisting, sure.
In general it will behave same like bind or dnscrypt
Via Console:pkg install os-unbound-plus-devel
It will only add a submenu to Unbound. It will be similar to dnscrypt dnsbl section, just give it a spin
It's a multiselect list, you cant use own ones ...