Are their any feats that boost Fear saves?
Maybe something similar to Iron Will but specifically against Fear?
This answer assumes the creature does not want to take a feat that simply renders the creature immune to fear—like the regional feat Fearless (Player's Guide to Faerun 38) or the more prerequisite-intensive vile feat Abyss-bound Soul (Graz'zt (Fiendish Codex I 83)) (Elder Evils 11)—, perhaps because the creature wants to realize the benefits of the feat Craven (Champions of Ruin 17).
As the question asks for feats similar to the feat Iron Will, none of these feats have daunting prerequisites, although their types may limit their availability. With that in mind, the feats below are listed in likely order of availability; as always, ask the DM. Urge the DM to be generous: The character may need special dispensation to take a feat that grants bonuses against fear, but it's not like the character's asking for special dispensation to take a feat that grants shadow pounce or simulacrum 1/day or something. (And, no, I don't know of any feats that do either of those things.)
Also of interest may be feats with beefier prerequisites like Indomitable Soul (Player's Handbook II 80), Trophy Collector (PH2 83-4), or Unnatural Will (Heroes of Horror 124) and with stricter type requirements like Steadfast Loyalty (from Savage Tide Player's Guide 4 and which requires the character to be from the Champion's district of Sasserine). However, unfortunately, it appears no general feat from an official source that has no prerequisites has as its benefit that the creature taking it gains, like, a +3 or so bonus on saving throws against fear.
Unnatural Will (Heroes of Horror)
Add your Charisma modifier to all Will saves against fear effects. This bonus stacks with any Wisdom bonus you might have to Will saves.
Cumbrous will (Savage Species)
Before rolling a Will save, you can decide to activate this feat, which gives you a +6 bonus on your saving throw. After the saving throw is resolved, regardless of the result, you are shaken until the end of the encounter. A shaken character takes a +2 morale penalty on attack rolls, checks, and saving throws.
If you have poor wisdom score in comparision to other abilities, you might be interested in Steadfast Determination (Player's Handbook II) or Keen Intellect (Oriental Adventures) to use Consitution or Intelligence modifier instead of Wisdom.