You could create a default SNAT, but a virtual server with SNAT enabled is going to be more specific and configurable than a SNAT. So do you want to basically route any requests from the internal hosts to any arbitrary destination host? If so, a 0.0.0.0:0 virtual server will work. Make sure to only enable it on the internal VLAN. If you have a pool of gateway servers you want to load balance, you'd want to add them to a gateway pool and use a Performance Layer4 VS with a FastL4 profile. If you just want to use the LTM routing table to send the traffic on, you can use a Forwarding IP VS.
You might try searching on AskF5 for phrases like "outbound access" or "virtual server types" for more details. The LTM config guide for your version will also have some useful reference material.
Aaron
Nimbostratus
