The IA has tried distributing their stores, but nowhere near enough people actually put their storage where their mouths are.
Typically because most people who have the upload, don't know that they can. And if they come to the notion on their own, they won't know how.
If they put the notion to a search engine, the keywords they come up with probably don't return the needed ELI5 page.
As in: How do I [?] for the Internet Archive?, most folks won't know what [?] needs to be.
What are some legal torrent trackers?
Depends on the jurisdiction. Remember what happened in the The Pirate Bay trial?
To me that's not even related to it being a torrent tracker, just that they were "aiding and abetting" copyright infringement.
In Law the technicalities matter.
Trackers generally do not host any content, just hashcodes and (sometimes) meta data descriptions of content.
If "your" (ie let's say _you_ TZubiri) client is distributing child pornography content because you have a partially downloaded CP file then that's on _you_ and not on the tracker.
The "tracker" has unique hashcode signatures of tens of millions of torrents - it literaly just puts clients (such as the one that you might be running yourself on your machine in the example above) in touch with other clients who are "just asking" about the same unique hashcode signature.
Some tracker affiliated websites (eg: TPB) might host searchable indexes of metadata associated with specific torrents (and still not host the torrents themselves) but "pure" trackers can literally operate with zero knowledge of any content - just arrange handshakes between clients looking for matching hashes - whether that's UbuntuLatest or DonkeyNotKong
On the other hand I also believe that a tracker that hosts hashes of illegal content, provides search facilities for and facilitates their download, is responsible, in a big way. That's my personal opinion and I think it's backed in cases like the pirate bay and sci hub.
That 0 knowledge tracker is interesting, my first reaction is that it's going to end up in very nasty places like Tor, onion, etc..
Most actual trackers are zero knowledge.
A tracker (bit of central software that handles 100+ thousand connections/second) is not a "torrent site" such as TPB, EZTV, etc.
A tracker handshakes torrent clients and introduces peers to each other, it has no idea nor needs an idea that "SomeName 1080p DSPN" maps to D23F5C5AAE3D5C361476108C97557F200327718A
All it needs is to store IP addresses that are interested in that hash and to pass handfuls of interested IP addresses to other interested parties (and some other bookkeeping).
From an actual tracker PoV the content is irrelevant and there's no means of telling one thing from another other than size - it's how trackers have operated for 20+ years now.
Here are some actual tracker addresses and ports
udp://tracker.opentrackr.org:1337/announce
udp://p4p.arenabg.com:1337/announce
udp://tracker.torrent.eu.org:451/announce
udp://tracker.dler.org:6969/announce
udp://open.stealth.si:80/announce
udp://ipv4.tracker.harry.lu:80/announce
https://opentracker.i2p.rocks:443/announce
Trackers can hand out .torrent files if asked (bencoded dictionaries that describe filenames, sizes, checksums, directory structures of a torrents contents) but they don't have to; mostly they hand out peer lists of other clients .. peers can also answer requests for .torrent files.
A .torrent file isn't enough to determine illegal content.
Pornography can be contained in files labelled "BeautifulSunset.mkv" and Rick Astley parody videos can frequently be found in files labelled "DirtyFilthyRepubicanFootTappingNudeAfrica.avi"
Given that it's not clear how trackers could effectively filter by content that never actually traverses their servers.
I also indicated above that having knowledge of .torrent manifests is problematic as that doesn't provide real actual knowledge of file contents just knowledge of file names ... LatestActionMovie.mkv might be a rootkit virus and HappyBunnyRabbits.avi might be the worst most exploitative underage pornography you can think of.
Some trackers are also private and require membership keys to access.
I was skating a lot as TZubiri seems unaware of many of the actual details and legitimate use cases, existing law, etc.