With the recent controversy over the sale of adsb Exchange I am not initially thinking of ceasing feeding but I have looked at two other, apparently not for profit sites.
Opensky-network seemed interesting but @abcd567 commented the forum very quiet so may be dying out, it does still share data though so worth a look…
adsbhub.org is interesting, the aim appears to be sharing data, there is no forum I am aware of so not sure how enthusiastically it is supported. Once you feed them they activate a return feed which is global that can be fed into VRS or similar.
Pretty sure, like adsbX it is unfiltered.