Anarcho-communism is the ideology espoused by people like Kropotkin and is pretty much the left-wing of anarchism. They emphasise collective modes of organising human economic and social life. They see a moneyless, stateless, classless society as desirable and strive towards that, so they are communists. They reject the necessity of the dictatorship of the proletariat to facilitate this transition to communism, which distinguishes them from MLs and makes them anarchists. I take most people to be ancoms when they say they are anarchists in leftist forums.

Individualist anarchism is pretty broad, but I think most people that call themselves this think of people like Stirner and mutualism and all that. It comes off to me as market-anarchism and just liberalism with extra steps, which I don't think is a sectarian comment to make since I don't even think this is much of a left-wing ideology at all. They advocate for an early stage of capitalist society, before primitive accumulation kicks in and everyone still owns the products of their labour as small proprietors and can do as they please with it, like sell it on the market. I might have this one wrong since I was never an individualist anarchist, but this is what I gather from looking at people talk to these types online.

Don't know what collective anarchism is, seems like people who are functionally ancoms trying to drop the label of communism.