Claimbrand
Claimbrand checks whether a brand name is available as a social media handle and a domain across supported social networks. Enter a name and the first five results are free. For a one-time $7 Brand Report you get full results plus an ongoing watch for that one name. Pro adds availability reports for multiple names, scheduled watches, a monitoring timeline, and alerts after a detected change. If you would rather not register handles yourself, account signup on chosen networks is offered as a separate one-time service. There is no sales call and no contract. Claimbrand does not take down or recover accounts, reserve names, or decide whether an account is an impersonator, and a taken handle can belong to a legitimate user. Automated coverage varies, and some checks come back inconclusive and need manual confirmation. Claimbrand is not a trademark search and not legal advice. Disclosure: I work on Claimbrand.