I'm making a homebrew subclass and I'm still fairly new. I'm trying to make an ability that adds attack accuracy to all weapons. I have chosen Bonus for my Modifier Type but there are no "All Attacks" in the Modifier Subtype. Is there anything I can do?

I'm not sure what you mean by attack accuracy. Are you wanting the class to be proficient with all weapons or are you wanting to add a flat increase to hit for all weapons?

Flat increase to hit

I'm fairly certain you can't do just a flat increase to hit, I believe it's both to hit and damage tied together with Bonus: Magic and then whatever the modifier you want (+1, +2, etc).

I've never tried to do ONLY a bonus for to hit, so I certainly don't have the definitive answer.

*edit* A thought occurred to me right after I hit post. I'm not sure you can even do this for a subclass. I've only done it for weapons and items.

Thanks!