A low profile (<3mm, don't care how wide) SMD capacitor, about 10uf, rated at least 35V, which doesn't "sing" acoustically under pulsed loads like PWMed LEDs.
For lower voltages, alu. or tant. polymer caps are great but seems nothing exists at higher voltages.
(and yes, I've tried the Murata ceramic ones that are supposedly quieter. They're not)
Something like a 74HC138 or HC595 with P-channel MOSFET outputs that can source a couple of amps.
A 20mA class RGBW LED from a brand-name manufacturer like Osram etc.
An RGBW LED with on-chip 1-wire driver from a manufacturer that can be trusted for long-term reliability. Ditto white only.
A 16 channel, 100mA per channel ES-PWM LED driver with sensible 1-wire interface and internal regulator for its logic supply that can take up to 30V
A PIC32MX part family with 3-5V supply and IO.
A small 3.3V LDO that cuts off and draws negligible power below 3.4V in ( for use with unprotected LiPo cells)
0R resistors in 0803, 1203 and 1803 packages, for jumpering on single-layer aluminium PCBs
An FPGA family in SSOP-28,QFP/QFN28,48 and 64 with a buttload of Block RAM
A quad N-channel 500mA MOSFET with common source and series gate resistors (to limit slewrate) in a 10 pin MSOP