never use stock fl voice clips, man do they suck.
I can't really state a place to go for plugins, but i can tell you some essential names you will want to look up. and purchase or (retrieve..somehow nadadamean)
anyway, vengeance essentials club sounds, and anything vengeance essentials for samples.
soft synths - sylenth2, synapse dune, ni massive, zebra2, rgc audio z3ta, synth1,
are some really easy to use synths
you will need to find a piano vst, u can look up sound fonts for those, because fl keys just doesnt cut it