In terms of what's been added to the electrified network since 2010, there's not really been much that is useful for freight yet.
The biggest one is Gospel Oak - Barking, which has made future electric to Thames Gateway (+Purfleet/Dagenham/Tilbury) more practical, as already discussed.
In Scotland, Cumbernauld line electrification gave access to Grangemouth, and wires have gone up there accordingly. Although I suspect it wasn't that inconvenient just to switch over at Mossend before.
In the north west, you could potentially switch some Liverpool (Seaforth) to Scotland containers if you could find somewhere sensible on the docks branch to switch over traction. But that's not many a week.
GWML needs wires all the way to Bristol/Avonmouth/Wentloog before anything noticeable can be switched. We've only got the last of these 3 so far, and only recently. Even that looks like it's more usually pathed via Chippenham. But it does mean the link at Acton is finally worth a discussion.
MML needs wires extending to Nuneaton and/or Toton before it starts to be useful. But even at that point you're almost just providing an alternative to the already electrified WCML.