Problem:
When you take the Barbarian Dedication feat, you get trained in Athletics and access to the Rage ability. You also pick an instinct and get that instinct's anathema. You can later take another Barbarian archetype feat to get the first instinct ability.
Looks fine for most instinct choices. Except for Animal Instinct. That instinct anathema says that you can't use weapons while raging. But the multiclass archetype doesn't give any improved unarmed attacks until you get the instinct ability (unless you already have a better unarmed attack from some other source). So for at least two levels of play, your multiclass Barbarian could Rage, but it wouldn't be a very good idea. And if you take Barbarian Dedication at level 2, it is even worse. Barbarian Instinct is a level 6 feat - so that is four levels of bad unarmed Rage.
One solution that I came up with is to houserule that the second part of the anathema only applies after taking the Barbarian Instinct archetype feat. Before then, you can use weapons while raging without violating anathema.
Does anyone have any other options to use for this that don't involve house rules?
I hate to call it a trap option, but that is what it feels like.
There are also all of the cases where your primary class or ancestry provides some type of unarmed strike, where the anathema is hardly crippling.
when you break the anathema you only lose the instinct ability, which you don't have if you don't have the instinct feat. So basically breaking the anathema doesn't have any effect.
I suppose that works. Though it more gives justification for what I was calling a houserule earlier. With that in mind, it becomes more of a thematic interpretation since mechanically the two are identical. Since the penalty for breaking anathema is non-existent until taking the Barbarian Instinct feat, then we may as well not apply anathema until that feat is taken.
There are also all of the cases where your primary class or ancestry provides some type of unarmed strike, where the anathema is hardly crippling.
I can only think of a small handful of them though.
Monk is the first one that comes to mind. Some of the stance attacks don't have Agile trait, so those would all work quite well.
There is also Champion's Deific Weapon feature. Though that one requires specific deity that has unarmed strike as favored weapon. Also it only increases the damage die by one step (usually to a d6) and it still has the Agile trait which halves the damage bonus from Rage.
Sorcerer can get Dragon Claws, but again only for particular builds. Also I am a bit wary of trying to combine spellcasting classes and Barbarian Rage. It is possible, but takes quite a bit of work.
Goblin ancestry would work nicely. But you have to actually be a Goblin since the feats that grant unarmed attacks have specific heritage requirements.
Half-orc has the Tusks feat.
Lizardfolk have a couple as well.
Are there any that I have missed?
You've also got cleric, similarly limited to champion.
You've got the wild druid giving themselves claws.
You've got the mutagenesis swilling alchemist.
Characters with another source of unarmed attacks better than the standard fist (a number of which are Agile) are still a minority of the options, but there are enough of them to be relevant to this question.