The 2nd one is done by sending packets/nms, as for the first one, I imagine it's an invisible ocelot being teleported to the location of your head every tick (very resource intensive)...
Tyep If you want someone to make a plugin for you, go to the request section. If you're actually looking to figure out how to do this then you could start with this: Code:java Location loc = player.getLocation().add(0,1,0); player.getWorld().playEffect(*whatever arguments go in here...use the loc*);
You can only do some of these particles through NMS. [mod edit: Deleted some posts below this one advocating unsupported, unofficial builds]