I recognize them, but haven't checked out Serfs or FarronBalanced. As for the others, although they have left tendencies and typically quite topical content (and thus have value to algorithm hijacking), they are, at their furthest extent, near the inside edge of "permissable" discourse and don't really push that boundary. Depending on what your looking for, there are a lot of channel options that will leave the overton window and get down to theory, practice, histroy, commentary, and and/or brass tacks with content less palletable to the predominant capitalist-molded discourse.

As far as recommendations, one that I have enjoyed quite thoroughly is Marxism Today, previously called Marxist Paul. He has great content from the perspective of revolutionary Irish national liberation. and does some great in depth videos on theory and history, as well as current movements which definitely do not get covered by any major Western media.