This isn't a useful area. It's mainly just build ideas to point to. Unlike my other builds, don't consider these complete or without problems.
No one managed to find a 3rd permanent benefit gained through a printed adventure that had no cost. Extra retard points go to soro for listing rituals & magical locations that (unlike the one mentioned in the OP), you know, have costs. So since no one else was able find a third example, I finally did: Dungeon Magazine 153's 6th page of Touch of Madness has an artifact called Tears of Ioun that with exposure (but not ownership) gives the Aberrant Blood feat to humanoids. The real question became how to find it. This brings me to:
One explosion later that commoner level transforms in only a path to become the world's best detective ... if you need to find things.
Human Psion 5 / Chameleon 5 / Cerebremancer 5 / Psychic Theurge 5
Either Psychic Reformat (you are a psion, after all) yourself to go from a Shaper to a Seer after your last Chameleon level (you'll have the levels to support the prereqs with the cross-rank skill cap and thanks to able learner it does not cost any extra skill points) or retrain. You can also be an Apprentice(Criminal) [DMG2p177] with the Skil knowledge [UA81] feat at 3 for Bluff & Disguise but it isn't as elegant. EDIT: See the Magical Training + sanctum spell + southern Magician / alternate source spell feats below. These could eat up your flaws and 6th level feat, but your 9th-18th level feats are still open.
Finding important things or powerful people has always been tricky in D&D. Its balance is of concern to every murder mystery or behind the scenes, powerful wizard story in a multitude of campaigns. The go to sources for core attempt to locate a creature or locate an object are woefully underpowered, purposely. Anyone with mind blank, form-changing, mislead, or nondetection laugh at these spells even if you happen to be within 2000' of a fully buffed circle mage who has cast these spells to find you. The same goes for objects (nondetection or PAO only). There are additional restrictions of needing to know exactly what you are after, especially when Vecna blooded is in play. Most players looking for something don't know a target's exact nature. They certainly won't have it less than a half mile away.
The solution (for important things) is time. Characters under level 11 typically don't have access to means to defeat standard divinations and people generally don't want to find nonlegendary items. The Finder doesn't have time to find your favorite spoon. He uses the Legend Lore spell that allows a bard (or high level wizard or even higher level cleric) plus 3 days to almost 3 and a half months (average of 2 months) to "fish" for information based off intercepting legendary information.
Normally Legend Lore has a limit. Specifically it can get you detailed information about what you are looking for. But it can't get you exactly what you want. This is where Hypercognition comes in. It can help you deduce the exact location of what you want. But it needs enough "fuel" to zero in on your target. A nice DM might allow your standard PC to simply hire two separate NPCs to do the castings for you. This bends the rule that most NPCs offering casting services won't accompany the PC. But even more than that it could be very plausible that a standard seer 20, even after being dropped in the correct place and after being told the relevant information from three Legend Lore castings may not have enough experience with the castings to use it as fuel for Hypercognition. Only by having them in the same character is it a likely guarantee. Of course this won't work well with rapidly moving targets, but that opens up other potential information leaks which may result in more normal methods working.
Sample use of "The Trick":
The Finder can be hired to get a PC to the Tear of Ioun so that the PC can benefit from the bonus after exposure. How the PC knows about the effects of the Tear of Ioun is left as an excersize to the reader, but the sample NPCs with the listed bonus feat is RAW.
The finder takes the time to cast Legend Lore three times. The first time, the Finder only knows of the Tear of Ioun as a rumor. It gives the vague and incomplete information that Tear of Ioun isn't what it used to be after being used by the Kaorti. This directs him to more detailed information, allowing a better legend lore result next time. Specficially, Legend Lore reveals that the Kaorti using the Tear of Ioun happened long ago, according to legend, near the small town of Wellspring near the Kadagast Mountains. The last Legend Lore casting could take place in the town of Wellspring (the Finder can teleport/shadow walk, etc). It doesn't take long for the last Legend Lore casting to point to a deserted tower in the Kadagast Mountains past the Harrow Wood.
Upon an instant visit to this location, Hypercognition can deduce the location of the stole Tear of Ioun by illithid agents of an illithid named Shathrax residing in a fortress under Wellspring. Now standard methods (stone tell/location item/locate creature/etc) can be used to directly locate the Tear of Ioun after returning to Wellspring. Upon doing so, the Finder will have earned his pay of time+spells.
Why This Build?:
Could a lot of other builds do this? Yes. Could RAW cheese my like triple 9 build do this? Yes. But this build is elegant and does the trick even when using the balanced spellcasting progression (with no 9th level spells or powers): Specifically all 6th level spells and powers plus any 7th or 8th level powers you want to learn via an 8th level, power-swapping only version of psychic chirurgery. For those who haven't read over the last year this basic part of my 3e fixes, here is how to equalize spell progressions for all classes: a maximum of 0th spells are gained at level 1, 1st level spells at level 2, 2nd at level 4, 3rd at 6, 4th@8, 5th@10, 6th@13, 7th@16, & 8th@20. For psionics you can already manifest anything of your ML (still have the PP of a psion 15) and with a major BL and Practiced Manifestor your ML=15+3+4 without Overchannel. Those could be your 2 [psionic] feats if you have nothing better to do.
Michael Clarke Duncan (in the picture) died three months after the show. It was his last time on-screen.