1) Anon 2) At once 3) Before you know it 4) In a flash 5) In a heartbeat 6) In a snap 7) Pdq 8) Quick as a wink 9) Raway 10) Readily 11) Right away 12) Right now 13) Rightthissecond 14) Soon 1) Asap 2) Celebrity magazine 3) Chop-chop 4) For not having moved quickly 5) Frequently exhibiting 6) Immediately 7) In a punctual manner 8) In nothing flat 9) Italian phone greeting 10) Lickety-split 11) Now if not sooner 12) Promptly 13) Quickly 14) Readily 15) Relative of tout de suite 16) Slang for now or immediately 
Pronto is slang for now or immediately.
promptly; quickly.