This Design Idea describes a simple way to form a reliable astable or monostable multivibrator from a set/reset latch. You may find it useful because it. ... which you can build with two NAND or NOR ...

The internal circuit of a single 7400 dual-input NAND gate. 30px MovGP0 (CC BY 2.0 DE). ... so having secured a few we could hook up an LED or make an astable flip-flop if we wanted to.