I have had periods when we did not have anchors, and periods when we did. The presence or absence of anchor members can absolutely change the vibe within the space so it is well to choose them with some care.
If your space and approach allow for permanent memberships with dedicated space, this is where your anchors end up; or at least, i have never had an anchor who was not a fulltime member with a dedicated space. I think it is possible but have not yet experienced it so I can’t talk about that.
The first anchor in Kamer52 was coincidentally a psychologist. (I would like to say I did this intentionally as I advise others to do but the truth is that I bumble my way into almost everything, and into this also). Because she was there, we found that in an organic way other people in the healthcare/mental health sector were attracted to us – so think broadly, in terms of mindfullness, wellness, food and food supplements, and so on. This continued on as she moved and other who had previously been part time members, moved up to full time.
Then because of some local development (the city built a medical center dedicated to this sector) this cluster of folks pretty much went away. This was startling and is one of the downsides of having an anchor; though the coworkers we had who moved there have at least in part remained connected with us. This and some other things led to our explorations in the area of the intersection between webshops/internet businesses and our space. So we pivoted to try this out, and are still tinkering with it. In general it has been a wildly positive experience, but the problem of the sprawling and messy nature of logistics (packing, returns, et cetera) for webshops has not been entirely solved.
In general the best anchors are the ones who think of coworkng as a decision they have made, not as a temporary solution until they get big enough to have a “real” office space. To a large extent they do set the tone for the space for everybody else and in some ways the community begins to revolve around them.
We had a period when the dominant presence was private employee work at home types, most were moms with a part time gig. It was a friendly, cheery, “escape” kind of vibe during that time. But I would not qualify them as anchors, as they did not appear regularly enough for that. It did spin off into an anchor group, which still meets here once a month though most of the folks in the group only irregularly work here now.
Sorry if this is disjointed, I am really badly jetlagged today and also avoiding my inbox. 
Cheers,
Jeannine