You can add an aura to a player with
Code:
int iEntity = CreateEntityByName("info_particle_system");
float vPos[3];
GetClientAbsOrigin(iClient, vPos);
TeleportEntity(iEntity, vPos, NULL_VECTOR, NULL_VECTOR);
DispatchKeyValue(iEntity, "effect_name", sEffectName);
SetVariantString("!activator");
AcceptEntityInput(iEntity, "SetParent", iClient, iEntity, 0);
DispatchSpawn(iEntity);
ActivateEntity(iEntity);
AcceptEntityInput(iEntity, "Start");
where sEffectName is the name of the particle effect (make sure you precache it first).
And if you want some pcf files for the particle effects, you have to either find a server with them and download existing ones, make your own, or pay someone to make some for you
