I have a ton of that stuff for Aquerra, so much it is hard to pick out any few examples. . .
Let's see an example of each race:
* Dwarves: Dwarves believe anything of importance should be discussed standing up, and always stand to receive news or make any business agreements.
* Elves do believe in and practice marriage, but have a very open attitude to love. It is not uncommon for elves of the same sex to marry and it has even been known for three elves that love each other greatly to all marry each other. These types of relationships are openly accepted in elven culture, but since this is most often misunderstood by other races, elves tend to think of themselves as superior in that way. An old elven saying is, Humans do not live long enough to learn the intricacies of love. They also have a less developed incest taboo than other races, and cousins and siblings are allowed to marry, as are nephews/nieces to their uncles/aunts. However, the taboo against romantic or sexual relationships with a parent/child is still very strong.
* Gnomes: All gnomes value their noses and talk of them proudly. A long and large nose is a sign of good luck and prosperity to gnomes. Ironically, humans use the term "longnose" to try to insult gnomes, who chuckle to themselves believing themselves complimented.
* Halflings: Morningfeast: Once a week, devout halflings have a very structured morning meal to honor their goddess Rhianwen. It is held in several halfling households, with several neighborhood families going over to a different family's home for the meal each week.
* Lizardfolk: Parenthood is not a strongly held custom among lizardfolk. Typically, lizardfolk young are raised collectively by a tribe, with familial-like bonds being made between "clutch-brothers", and whatever tribe elder a lizardfolk might happen to bond to by means of showing skill at a particular task. There is a high mortality rate among lizardfolk young, which contributes to this custom of no particular bonding with adults until they have lived five or six years. And, lizardfolk will eat their young under certain conditions.