Keep in mind that most of my tricks WILL fly in many standard games, so they're actually
useful for a lot of people.
The penalties of the Nightsighted trait and the light sensitivity special quality of kobolds and drow can be negated by a 10 gp item from Sandstorm (sun lenses). Likewise, the Vulnerable flaw + Luck of Heroes nets a +0 AC (-1 from Vulnerable, +1 from LoH), and +1 to all saving throws (even better if you're a halfling).
Necropolitan characters should seriously consider taking the Evolved Undead template, also from Libris Mortis. +2 Str, +2 Cha, one level 5-6 spell-like ability 1/day, and
fast healing 3. It's +1 LA, and is one of the few sources of LA that is very much worth it, even if you can't do LA buyoff (at least if you aren't a dread necromancer and can't do negative energy bursts at will). Very nice to have at early levels, when it's hard to heal and easy to die. If you CAN do LA buyoff, you should take the template multiple times,
because it stacks. Also, the Faerie Mysteries Initiate feat grants you your Cha bonus to your hit points, rather than your Con, so grab this to get a high HP score. Sorcerous necropolitans should have as many HP as the party's barbarian, if not more.
Any psionic character worth his salt (especially psychic warriors) should snatch up
psychic reformation in order to nab regular item crafting feats as well as the Extraordinary Artisan and Legendary Artisan feats (from the Eberron Campaign Setting). You can have exactly the items you need, when you need them (which is hugely needed for martial characters), and can get approximately 260% more
magical psionic items than you would without them. Even if you're a level behind, this can increase your power considerably more than you'd think, and the XP Gravy Train means you can catch back up in just a few encounters. Especially useful for characters that are higher level from character creation.
A slightly less powerful, but less resource intensive, variation on the previous entry is great for high-Int characters. Even without ranks in Craft, it's easy enough to triple your gp value as a first level character, if you 1.) take 10 on Craft checks, 2.) have an assistant or two (+2 for Aid Another, which is a perfectly reasonable function for an unseen servant, familiar, or psicrystal), 4.) have (non-masterwork) tools to prevent penalties (masterwork is better but not necessary), and 5.) have spells or class abilities that grant bonuses to crafting (see the factotum's Cunning Knowledge ability and the
guidance spell). A 1st level character that specializes in such things gets a 27 on his Craft checks (take 10 + 4 ranks + 3 Int + 4 Aid Another + 2 MW tools + 3 Skill Focus + 1 cantrip). You can make some nice masterwork equipment for far less money, and you can even use Crafting to create the masterwork tools used to make the rest of your items. If you have the right race or use
alter self (via a feat) you can even get some racial bonuses to toss on as well.
Heck, any character with that level of dedication can pump most any skill up to that level. Great for bards with Bardic Music and characters with Iaijutsu Focus (awesome for rogues to combine with sneak attack). Toss on some +2/+2 feats and a custom soulmeld or two and you've got a sky-high bonus at level 1.
Compression and
reduce person are great for Small characters, especially spellcasters (who are the ones that can get spells anyway). Note the benefits granted by Tiny (and Diminutive) creatures above and beyond what Medium-turned-Small creatures get.
Likewise,
expansion and
enlarge person are better for Large creatures (or creatures that are treated as Large, such as half-giants), since they get the benefits of being Huge (or Gargantuan), which are above and beyond what a Medium character gets from becoming Large (or Huge, as the case may be). There are times when +1 LA can be worth it.