I never followed P2P scene when it comes to ongoing manga, but during last ~8 years (back when big busts started happening) there's been a major shift to DDL sites and digital raws. 10 years ago all tankoubon raws and chapters were uploaded to Share first and they were all paper scans.
Nowadays, new raws are uploaded on haruka-yumenoato.net and then spread to various other DDL sites. For example Shounen Jump always gets uploaded the moment digital version is available, which I believe is the same day paper version is out. Early Korean and Chinese scanlations are coming out probably because they have people who can get the magazine before store date either by being a part of the supply chain - there was such person arrested not too long ago: https://www.animenewsnetwork.com/news/2015-11-18/2-arrested-for-uploading-the-seven-deadly-sins-manga-to-site/.95507
- or perhaps even hacking the online stores.
For LNs, depends on what you're looking for. For older series you only find paper scans, because they were scanned back when digital distribution wasn't a thing and nobody bothers to provide digital versions if available. When it comes to new ones, it could be because of lack of DRM tools (the DRM itself probably isn't that hard, there's not enough technical people to make tools for every store) or exotic formats - some sites like Honto don't provide .epub for all books, they use formats that only work with their readers like .lvf or .book, so even if you remove the DRM you still need to figure out the book format.
Amoeba I checked out, it doesn't have many original scans and definitely no magazines or light novels. The network is pretty slow, barely any new files. Winny is still popular according to this report: http://www.netagent.co.jp/product/p2p/report/201501/01.html
but last time I tried it I didn't have much luck.
Share has a good search engine so you don't have to run it to check what's available but it's down right now: http://keydb.telegrip.info/
There are private forums like UGCity where a lot of raws that don't make it to DDL sites get posted, but it's hard to get invited.
To sum up, P2P networks have been phased out by DDL sites that remain the best source of new raws for the general public.