I am not sure that I agree that the singular aspect makes the suggestions bad. I would interpret the singular as implying it is a place to get a domain (of which many would be offered).
I am not wildly enthusiastic about the ones suggested and probably agree with majority to keep searching. If I had to choose one it would be Transit as it implies a domain acquisition as a way to get somewhere which is a nice analogy. That being said, some will think it means transportation niche.
I think to know what is best, I would need to know more what type of domains you mainly plan to emphasize. Like for example prosper to me definitely means business domains and possibly even financial niche widely interpreted.
You have been successful in this business a long time
@frank-germany. Ideally a name than instils trust and implies your long term selling of domain names would be ideal.
Another question to ask is do you only do domain sales, or do you also see branding and naming consultation and analysis. If so, domain may be limiting.
More questions than answers. Best wishes as you consider rebranding.
Bob