- ctrl-enter : executes the current statement(s)
- F5 : executes the current code as a script (think SQL*Plus)
- ctrl-space : invokes code insight on demand
- ctrl-Up/Dn : replaces worksheet with previous/next SQL from SQL History
- ctrl-shift+Up/Dn : same as above but appends instead of replaces
- shift+F4 : opens a Describe window for current object at cursor
- ctrl+F7 : format SQL
- ctrl+/ : toggles line commenting
- ctrl+e : incremental search
Reference
[1] http://www.thatjeffsmith.com/archive/2012/11/keyboard-shortcuts-in-oracle-sql-developer/