A sigh can also help.
Turning your head slightly.
Sniffing the ground is also a calming signal and a calming activity, so if a dog is a little stressed scattering a few (fairly low value) treats on the ground (especially in grass) can help calm them - the key is that they are close together and easy to sniff out, as racing around trying to "find" a treat is stimulating...
And, while it's not a calming signal, I find asking for (having trained it) a hand-touch is also very calming for Honey - it refocusses her on me rather than whatever is causing her anxiety.