Getting back into emulation

It has been a long time since I have downloaded and used emulators. I am trying to get back into it because am going to be working on building an arcade cabinet. I see that Launchbox seems to be popular. I am trying to look into using that interface. Although I am guessing it is only an interface and I will still need to download emulators for each console. My question about ROMS is probably pretty stupid and please don't flame me, but I need to ask anyways. I am on the megathread looking at what is available. I saw it is best to look at the no intro sections under each console so I don't get a million verions of the same game that has been modded. My question is, do you have to download the ROMs individually or is there a way to bulk download them? I do have a VPN that I can use while downloading. If there is a post I missed talking about it, would you please link it for me.

Thank you. Any help is much appreciated.