Ponix + High Avatar Garunix

Using Fire King High Avatar Garunix in your combos comes with a catch - if destroyed by card effect, it comes back in the Standby Phase and destroys all other monsters on the field, potentially ruining your endboard if you're not careful.

The solution to this is to Special Summon High Avatar Garunix from the GY during your combo, ensuring its effect can no longer trigger.

That aside, the combos themselves are pretty much the standard Ponix + any Fire King lines, as High Avatar Garunix doesn't have any effects that can help you extend or otherwise improve the combos.

One thing to note is that most decklists only run 1 High Avatar Garunix, thus Fire King Courtier Ulcanix lines don't work here - she cannot Special Summon High Avatar Garunix if you don't have him in your Deck anymore.

Perform the Ponix + any Fire King lines if you open this starting hand, making sure to revive Fire King High Avatar Garunix during the combo so it doesn't blow up your field later!