How do you match on a literal exclamation point?

[nivekuil]

isearch matches ! literally, swiper can escape it as \!, but I can't figure out consult.

[minad]

Assuming that you use the Orderless default configuration, =! should do it. The trick here is that = is an affix style dispatcher, see https://github.com/oantolin/orderless#style-dispatchers. You can also set orderless-style-dispatchers to nil or customize orderless-affix-dispatch-alist if you prefer a different configuration.