chiefdogDid you test the particle effects here: https://developer.valvesoftware.com/wiki/List_of_TF2_Particles and they were unusable?
yes that's the list + i used this one aswell https://forums.alliedmods.net/showthread.php?t=127111
bday_baloon(s) also work and you can try eotl_ effects, since pyro_pool is used widely, so the others may also work
rule of thumb is to stay away from unusual effs, anything alien-like or effects that are meant to be played on repeat (candle flame, or flames in general)