You more often than not want to hold on to Gonk if he shows up in your opening hand. Playing him as early as possible is better for the combo, and may even allow you to combo early with faceless if your opponent doesn't clear it.
I theorycrafted my own odd druid featuring Gonk before Rastakhan’s release without realizing the OTK potential of the card. Similar to what I saw Toast make, this instead uses Witching Hour instead to set up the OTK, meaning Gonk needs to be the only beast in your deck (besides Baku of course).
If you haven’t seen the current OTK Gonk yet, essentially if you have multiple Gonks on the board, their effects stack, allowing you to clear all of the enemies on the board and hit (aka GONK) your opponent multiple times for tons of damage!
Instead of using Prince Taldaram, This uses Witching Hour to revive Gonk for three mana twice and allowing you to hero power and Claw twice for a total of six damage. If your opponent has at least 5 minions and no armor, this would easily OTK them. Here are the reason for some of my choices:
Saronite Taskmaster is actually a great card in this deck since it can put a minion on your opponents board to Gonk.
Leeroy Jenkins is great for opponents who have too few minion in play, allowing you to gonk the welps that Leeroy creates (as well as an extra 6 damage to face)
Dreampetal Florist is a tool to set up a harder combo. Its a bit tricky with Baku in hand (since buffing Baku is pretty much a bust because you DO NOT WANT TO PLAY IT) but the chances are still good with multiple minion in hand like Faceless, Gonk, and Leeroy.
***DO NOT PLAY Baku the Mooneater UNLESS YOU ARE TRULY DESPERATE. IF BAKU DIES, YOUR WHOLE COMBO COULD BE RUINED!!***
One card I think could truly make this combo deck even better is FLOOPS GLORIOUS GOOP. If you add this as part of your OTK, you could easily destroy all your opponents minions, and get mana crystals to buff yourself even more. I am tentative to craft it so if anyone tries it, please let me know in the comments!
I’m open to any feedback in the comments! Thanks!