Folate (vitamin B9) promotes cardiovascular health and is needed for several cellular functions. Some natural sources of folate include grains and legumes, definitely non-paleo. I know liver has a good amount of folate but I happen to hate liver though! Although I have eggs or green vegetables, I understand that I am still far away from the recommended intake of folate. Any paleo ideas on how to increase my intake of folate without going into supplements?
Nutritiondata.com shows that mollusks and crab are decent, if not super-rich, sources of folate. Raw egg yolks, too, but you already mentioned eggs. All the plants that show up, from seeds to spices, require ingestion of ridiculous amounts to meet the recommended intake.
I've been looking into the same thing lately, but fortunately, I do like liver. Still, my husband doesn't, so I have to save that for nights he's out. Good thing he's not trying to get pregnant or anything. ;D
Leafy greens (also, asparagus) and liver are your best 'paleo' bets. Personally I love leaves and usually eat a whole bag of frozen spinach or collards with my dinner, but I know they're hard for some people to incorporate in large servings. Try to find a way to hack liver; different livers taste very differently (I love calves liver and even beef liver, but dislike the flavor of bird's livers), and there are many ways you can prepare them beyond sauteed with that strong taste. They are easy to mush up and add to a variety of dishes. Liver has so much folate if you ate a good serving twice a week or so you wouldn't have to worry about maximizing other sources.
I also eat chickpeas pretty regularly and black beans every so often, both are a good source. Obviously if you're a purist this won't work for you.
If you're not trying to lose weight, then ferment lentils (also high on iron and manganese). While lentils are legumes and are not allowed on Paleo because of their lectins, research has shown that just like with soy, when properly fermented, most of their lectins are going away. More info and links: http://eugenia.queru.com/2012/04/19/fermenting-lentils/
Other than that, and leafy greens/mollusks, you can supplement with folate, it's easy to absorb (just make sure it's not folic acid, but actual "folate").
Check out the whfoods site on folate: http://www.whfoods.com/genpage.php?tname=nutrient&dbid=63
At the top they only list greens and beans, but on the bottom they list many more foods, many of which have 10-20% of the DV for folate, including (as someone else has mentioned) avocado (1 cup has 30%), papaya (1 has 29%), and beets (1 cup raw has 37%, not sure what cooked would be). I'm not sure why they don't list more of these foods at the top of the page.