Further more!
There is a secret rule in which these words fall in.
Any verb that has "ll" in its infinitive is conjugated with "ll":
Hence Hallar - hallé - hallaríais.
If it does not have "ll" in the infinitive, all its conjugations are with "y":
Hence "no creo que Haya hallado las llaves del coche aun", "te llamaremos cuando hayamos hallado el lugar", "cuando hayas hallado la clave todo será cuesta abajo".
The hack is if you know the infinitive, you know how to handle the rest. I am a native speaker and I often have to remember this.
...and then there is the tree, el haya, el hayedo y los hayucos.