Where can you download FL Studio plugins?

By "packs", you can download literally hundreds of free VST plugins that FL Studio will instantly recognize and use at your disposal (once located and activated by FL). If you remember where you installed the VTS Plugins folder, just drop any of those plugins there, have FL refresh the plugin list and tick it off as a useable plugin. Then just add the device as another instrument.

Keep in mind that many plugins don't use the FL Studio generic interface and most will probably not offer individual automated "edit events" options, but if used correctly, any knobs you tweak during a recording will appear as an event on playback. For some plugins that don't even have an interface, FL Studio will assume a generic one with all of the FL specific functions.

You don't need to use any additional plugins at all as FL comes with many very good ones, but if you have certain sounds in mind that you would rather not reproduce with Harmless, Sytrus, Wasp, etc., you may be able to find a plugin that has exactly the sound you are looking for it their presets.