No Class Levels

[StrangeLooper]

What happens if you have no class levels, only hd, because of templates and such? Do you get a bonus feat on your first hd?

[Psyren]

What happens if you have no class levels, only hd, because of templates and such? Do you get a bonus feat on your first hd?

Yes, followed by feats every 3 HD as normal. See MM1 pg. 290 at the bottom.

Note that most templates don't add HD; they add LA, which is different and does not grant feats.

[Particle_Man]

That is at chargen. Mind you, eventually, you would gain experience points as you go adventuring and I think you would then get class levels, if you advance at all.

[Fax Celestis]

Depending upon your racial selection, there's nothing stopping you from advancing by HD. Say, for instance, you played a worg: the advancement line clearly indicates you can advance by Magical Beast HD. There's virtually no reason to do so (barring some exceptions, such as the Feral template and natural size increases), but it is a thing you can do.

[Telonius]

Do note that in the Humanoid (http://www.d20srd.org/srd/typesSubtypes.htm#humanoidType) type:

Humanoids with more than 1 Hit Die are the only humanoids who make use of the features of the humanoid type.

So this would only apply to non-humanoids, or things like Lizardfolk or Locathahs that have the Humanoid type but start with at least 2HD. You couldn't be (say) an Elf or a Human with just a racial hit die.

[Urpriest]

Depending upon your racial selection, there's nothing stopping you from advancing by HD. Say, for instance, you played a worg: the advancement line clearly indicates you can advance by Magical Beast HD. There's virtually no reason to do so (barring some exceptions, such as the Feral template and natural size increases), but it is a thing you can do.

Depends on what "you" are. Advancing by HD is a way for a DM to make more powerful monsters, or arguably a player to have a more powerful base race. That doesn't mean that you can just spend XP and gain RHD like you do class levels, though: higher RHD races have lower LA for the same abilities, so you can't assume that you know the formula for gaining RHD over the course of play (unless you're a Dragon, for which the formula is written in Draconomicon).

That said, the OP should know that every creature, no matter whether they have class levels, gets a feat at 1 HD, and that that feat is in no way shape or form a bonus feat. If the OP didn't know that, they should read a monster statblock at least once, and probably read my Monster Handbook (link in sig).