If a character who has a familiar dies and is then raised via raise dead or even reincarnation, is the familiar still bound to that character or is that bond broken at character death?
Death of a Master
If a master dies and the familiar survives, part of the master lives on in the familiar. It loses any extra hit points and skills it gained from the master but retains most of its familiar abilities. It is treated as having a master two levels lower (but never below 1st level). If the master is later brought back from the dead, the bond is reestablished, and the familiar gains whatever abilities go along with the master’s new level.
---Tome and Blood, page 12
Although published before the Dungeons and Dragons 3.5 Revision, anything not republished from Tome and Blood is still a source for Dungeons and Dragons 3.5 information according to Why a Revision? (DMG (2003), p. 4)
As long as that section of Tome and Blood is not reprinted or superseded by newer material, it still pertains to the rules at large.
Nothing in 3.5rd edition's rules suggests that the bond between a familiar and its master is broken by the master's death.
In fact, there seem to be no rules at all for what happens to a familiar when the master dies. Granted, it's hard to prove a negative, but in this case it's easy to check the parts of the rulebooks where we might expect to find such rules:
The "Familiar" class feature description on page 54 of the Player's Handbook doesn't specify that anything in particular happens when the master dies. Given that this section does describe in detail what happens when the familiar dies, this is where I'd expect to find any special rules for the master's death - and there aren't any.
The "FAMILIARS" sidebar (Bottombar?), on pages 52 and 53 of the Player's Handbook, also doesn't specify that anything in particular happens to a familiar when its master dies. This would be my second guess as to where to find information about what happens to a familiar when its master dies, as it's the single biggest section of the rules that deals with familiars. No such information is present.
3.5rd edition doesn't actually define the effects of death anywhere, presumably its authors assumed players would be able to guess. As such, there's nothing in the non-existent rules for death that describe what happens to bound familiars.
The rules for bringing back the dead on page 171 of the Player's Handbook contain no mention of familiars.
In the absence of a rule describing for what happens in a specific situation, it's generally safest to assume that real-world common sense applies; or if the situation is one with no real-world precedent, that the status quo is maintained. This is why we assume that spells don't end upon the caster's death, and that magic items don't cease to be magical when the spellcaster dies. Accordingly, we must conclude that, like Hachikō, a familiar remains bound to its master even after that master's soul departs for the outer planes through the nearest astral conduit.
Technically-unrelated bonus rule: The homunculous, listed on page 154 of the monster manual, isn't a familiar. However, it acts a lot like a familiar, and can fulfil most of the same roles. Its monster manual entry specifies that it dies and melts into a pool of ichor if its master is slain, which is disgusting, but thankfully not the norm for familiars.