I find the Dictionary of Sephardic Surnames (Dicionário Sefaradi de Sobrenomes) by Guilherme Faiguenboim, Paulo Valadares, and Anna Rosa Campagnano to be a valuable tool. It is not cheap, but can probably be found in major libraries. The book is a meta-index of surnames names found in dozens of academic works on the Western Sephardim. Those books, in turn, reference the archival sources which can then be consulted.
Clearly there is no way of knowing if a name in a book is a family member, but finding the surname in the right area
The Internet can be a dangerous place to research. There is an ever increasing volume of fantasy and misinformation being published, especially on the subject of crypto-Judaism and bnei anusim.
There are about a hundred groups and fan pages on Facebook that appear to cover our subject. Many of them belong to people with agendas. The Sephardic Diaspora group is the serious English-language Sephardic genealogy Facebook group.
There is also a Sephardic Genealogy fan page associated with this website.