Vayne/Nidalee/Varus. I enjoy poke champions the most & Nidalee has a nice way to follow up with the poke. Vayne because of her condemn and tank shredding which really makes you feel way more useful as an ADC.
Probably Garen. It's extremely satisfying to flash-silence a carry then kill them in one combo, while still being extremely tanky, and being able to rejoin fights with full hp after regening for only a few seconds.