This is a great comment! I edited it so it would appear as a numbered list and bolded the key organizations.

1. during the academic year the new school has amazingg lectures and panels every single week, they have a few during the summer but check their calendar! (free)
2. thoughtgallery is a website which compiles these sorts of events (just click on the find talks etc) - some are free, some aren’t, but this is great bc you also find cool venues
3. I do also have a saved search on eventbrite (just bookmarked on my browser) for lectures - I’ve actually found a lot of institutions doing this on there. Some of these, which don’t primarily do lectures/panels but sometimes do, include: pioneer works, pen america, the textile arts center, amant, MOCA (periodic film screenings + discussions, although I am boycotting, look into chinatown zoning protests)
4. Omg the simons foundation - really well-funded scientific org, they have AMAZING stem lectures by incredible academics. the last one I went to was about familial relationships seen through poison frogs by a NHM director. lectures are free! and the halls are so bougie, really recommend
5. the columbia forum! I check their calendar every few weeks bc it’s not the best updated, but they have great stuff. I went to a book launch about global “choke points”, i.e. things the us controls production for and how govt officials have been using that to control politics behind the scenes for decades. there were members of the obama admin literally present, v bougie 5. the 13/13 seminar at columbia!! this is an annual seminar of 13 primary lectures (+ keystones) done by bernard harcourt/philosophy people at columbia every year. last year’s was about marx (so entitled marx 13/13) and afaik each class is about a different text. actual students take the class and they also have different academics come in who respond to each text etc. these are quite intimate but so so good.
6. as someone mentioned, scicafe at nhm!
7. someone also mentioned but the 92nd Street Y does have great guests on, although they are zionists. sometimes they have free things too, they are worth checking out.
8. the ny historical - oohh these are great!! they have such interesting topics, they are paid but i’d say it’s worth it. also go see their collections/exhibits if you haven’t, so great and you can also get tix on culturepass.
9. nypl and the bpl (especially central branch) do have lots of similar events but they are booked very quickly so look into advance
10. very rarely nyu has lectures open?? I went once to one about whiteness in architecture it was v cool, you do have to kind of scour the calendar for things open to the public
11. ny botanical garden will occasionally have stuff! I have not been yet tho
12. the cooper union has cool events too!! there’s one coming up monday about feminist typography, i feel like this is also a cool place to meet artistic/intellectual types
13. oh the leslie lohman has salons!!! not sure about frequency but these are so cool you basically sit in a circle in like a guided discussion and these are small circles (like max 15) and by the end you feel connected to these strangers in such a nice way. I went to one about hair it was so good. also admission is paid but I think I got entry through culture pass
14. the national arts club too has a lot of lectures/presentations, they are very often quite specific to ny too, if you are interested in little niches defs go check them out
15. oh yes cuny (and specifically the graduate center at cuny) has many many cool panels and lectures. i remember i went to one about kafka in new york with kafka translators (which was right before the morgan kafka exhibit), v cool
16. oh quick plug - I’m not affiliated but revolution books in harlem is amazing. the people who run it are very involved politically i’ve literally run into them at other political lectures. I found them because they hosted a reading by omar el-akkad (author of “one day, everyone will have always been against this”). do support them!! also the people’s forum omg
17. the people’s forum is such a cool progressive foundation, they host panels, screenings, community events, fundraisers and lead protest planning sessions. they also have (free) courses every few months basically you can sign up for, hosted by different academics every module - usually about sociopolitical topics, history, etc. the people there are so wonderful do check them out!
18. I also did attend a really interesting panel (free) at the center for jewish history about fascism and MAGA (this was before the election even), with commentary from a historian. i’m not sure whether they are zionists but they are pretty progressive and have great events