If the exact domain you're looking for is not on the suggestion list, it's probably because someone else on the web already bought it. You can maybe choose for a different suffix, known as "top-level domains" (TLDs), such as ".io" or ".org" or any other you might like. Or, you can choose for a variation of the original name you wanted.
These domain suffixes (TLDs) are managed by the Internet Assigned Numbers Authority (IANA), which is run by the Internet Corporation for Assigned Names and Numbers (ICANN). In other words, we have no control over their availability.