Youtube - no joke, there is an absurd amount of amazing content on youtube. Yeah, there's also all the shitty pop music, cat videos, etc., but you can ignore that. You can find videos of great talks from amazing conferences, from NIPS to Strange Loop, C3, All Things Open, etc., etc. And there are videos of classes on all sorts of subjects, from schools including Stanford, Berkeley, MIT, IIT, etc. And then you get stuff like 3blue1brown, numberphile, etc. Seriously, I could spend all day on Youtube just soaking up knowledge.
jmlr.org - in addition to the journal articles themselves, the site hosts a huge trove of conference proceedings from conferences like ICML, COLT, NIPS, etc. http://proceedings.mlr.press/index.html
ijcai.org - all of the past proceedings from the International Joint Conference on AI events is online, going back to the very first one in 1969. https://www.ijcai.org/past_proceedings
dspace.mit.edu - houses (among other things) an archive of the "AI Series" papers, which includes classics from folks like John McCarthy and Marvin Minsky, etc.
I found this site [1] after I bought the book "What do you believe is true even though you cannot prove it?" and that led me to [2] but I can't remember how.
[1] https://www.edge.org
[2] https://aeon.co/
jmlr.org - in addition to the journal articles themselves, the site hosts a huge trove of conference proceedings from conferences like ICML, COLT, NIPS, etc. http://proceedings.mlr.press/index.html
ijcai.org - all of the past proceedings from the International Joint Conference on AI events is online, going back to the very first one in 1969. https://www.ijcai.org/past_proceedings
dspace.mit.edu - houses (among other things) an archive of the "AI Series" papers, which includes classics from folks like John McCarthy and Marvin Minsky, etc.
https://dspace.mit.edu/handle/1721.1/5460/browse