Use a sponge to soak up concrete mix in whatever shape you desire and let it harden into a hardened version of what you just cut out! Pavers or garden accents? (I would wear rubber gloves while dipping/soaking!
DIY Concrete Lightbulb Hooks or drawer pulls: Fill light bulbs with cement, tapping to release air bubbles. Stick screw head or threaded drawer hardware into cement. Let set/dry for 72 hrs. Break and remove glass.