I think I'm pretty happy with my current selection except for the motherboard. It is the cheapest X570 board there is. I've read some people who say it is OK and some people say it is terrible. I've seen a few different people say the board won't work well or at all with more than two sticks of ram. I really didn't want to cheap out on the motherboard with this build but all those X570 boards are so damn expensive! I've been looking at this board
ASUS Prime X570-P Ryzen 3 AM4 with PCIe Gen4, Dual M.2 HDMI, SATA 6Gb/s USB 3.2 Gen 2 ATX Motherboard
It is around $30 more than the ASRock board but if that extra $30 will get me a substantially better board I'll do it. I don't want to have problems down the road because I went with the cheapest motherboard available.
*edit
Forget that board I notice it is being sold by a third party seller with shitty ratings. Apparently straight from NewEgg the board is $149.99 which would make it an easy choice over the ASRock board but of course it is out of stock.
I've also considered this board
MSI MPG X570 GAMING EDGE WIFI Gaming Motherboard AMD AM4 SATA 6Gb/s M.2 USB 3.2 Gen 2 HDMI ATX
This one is $200 effing dollars! But seems to have good reviews. If I have to get that one I suppose I will but damn this is getting expensive! All the other components I am fine with but the motherboard is giving me shit! If I knew for sure what Bios version that first B450M board I posted came with I might just buy that. It is only $65! When I first started I thought I didn't want to cheap out on the motherboard so I'd spend around $100 or so on one. Ha! That was wishful thinking. I don't really know what I should do now. I've got the money to do it but obviously I don't want to spend more than I have too. Right now the CPU,Mobo and GPU are all about the same price each!
Maybe I could find a cheaper PSU to save $20 or so. This is the one I was planning on getting.
Raidmax Vortex Power RX-735AP-V 80 Plus Bronze $59.99
I originally picked that one when I was planning on keeping the R9 290X since it is a power hog. I'm not sure what size PSU I should go with but I did a quick look at others and didn't see any decent ones for much less.
*edit
According to the Newegg PSU calculator it is estimating under 400w. So 500W should be good enough I'd think.
RAIDMAX Cobra RX-500AF-B 500W ATX 12V v2.3/EPS 12V SLI Ready CrossFire Ready 80 PLUS BRONZE Certified Power Supply This one is $40 vs $60 so if it is good enough for what I need why spend the extra $20? I don't know much about the different certifications PSUs have now such as this one being 80 Plus Bronze. I assume that is good enough but really have no idea.