Rapidstrike and Improved Rapidstrike give claws pseudo-iteratives
The Rapidstrike and Improved Rapidstrike feats from Draconomicon allow claws to be used more often in a single full-attack. In addition to high BAB requirements (+10 and +15 respectively), they require that you be one of the following types:
- magical beast
There are LA +0 options for aberration (elan) and dragon (dragonborn, dragonwrought kobold, spellscale; all Races of the Dragon), but I don’t believe there are for elemental, magical beast, or plant. There are numerous ways to obtain these types after the fact, but most are very expensive.
Beast Strike allows you to add claw damage to unarmed strikes
Beast Strike from Dragon vol. 355 allows you to add the damage of a claw attack to an unarmed strike attack. This is otherwise a normal unarmed strike, i.e. you can use it for whatever attacks you like, you can Flurry with it, and so on.
Because Eldritch Claws base their damage on your unarmed strike damage, and then you add the Eldritch Claws’ damage on to your unarmed strikes, you effectively double your unarmed strike damage when you do this. And because it’s not really doubling (just adding the same thing twice), it is multiplied, e.g. on critical hits, rather than 3.5’s usual multiplier-addition.
But also note that Beast Strike is a rather poorly-written feat that causes a fair amount of confusion. We have a couple of questions on it as it is:
The answers to both questions is we can’t say for sure because Beast Strike is a rather confusing feat. That said, confusing though it is, it’s a good feat, and I don’t mean that it’s super-powerful. It’s a reasonable buff to a certain niche build, and I think it improves the game for it to exist, even if you do have to houserule a few things in because the feat is vague.