pfSense

According to the documentation here:
https://doc.pfsense.org/index.php/What_are_Virtual_IP_Addresses

Virtual IP type of Other should behave like Proxy ARP when it comes to defining a group of VIPs with a subnet mask. For example, if I create a Virtual IP type of Proxy ARP and specify a Network rather than a single IP address, I see a list of all IPs in that subnet presented when configuring NAT (outbound). There is also an option present when setting up the VIP that states:
Expansion: Disable expansion of this entry into IPs on NAT lists (e.g. 192.168.1.0/24 expands to 256 entries.)

Following the same process for VIP type Other does not present an expanded list of IPs from the subnet. Instead it shows a single entry of the VIP with the subnet mask. For example, if I create a Virtual IP type of Other and specify 192.168.0.0/24 the only entry I see in my NAT drop-down is 192.168.0.0/24.

I've tested this on 2.4 and 2.6 - normal image and nanoBSD image.