There are a lot if good brands out there. Ideally you want one with actual folate instead of the (more common) synthetic "folic acid". That said, I had some special considerations (needed a prenatal that didn't contain Vitamin K, but did have all the things I was looking for), so I didn't start taking an actual prenatal until about a week ago. At 27 weeks pregnant. LOL. Before then, I simply pieced together the most important elements for any given stage. During TTC, folate was the most important factor-- so I took a freestanding folate supplement made by Solgar. I also took other things (magnesium, vitamin D, iron, activated B-12, etc) but the folate was my main focus.
When I finally became pregnant I kept on with the same regimen. I looked high and low for a prenatal supplement that would fit my needs. However, having no luck, I figured just taking key elements on their own would be good enough. It wasn't until very recently that I finally found my perfect prenatal. (No vitamin K, plus the active forms of folate and b-12... as well as iron and iodine which are both very important during pregnancy.) I've been taking it for a week now and feel great. It hasn't caused any digestive issues and the capsules are easy to get down.
"Baby Best Start" by Frontrunners Health. I think that have their own website, but I got mine from Amazon.
https://www.amazon.com/gp/product/B01400LX6A/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1