RLSA’s or Remarketing Lists for Search Ads is the use of Remarketing in Paid Search / PPC campaigns through Google Ads. RLSA’s are used in the audience feature and can target people who have previously visited your site, and can tailor your bidding to target those on Google search and partnered websites.
Remarketing lists are a great way to target those people who have previously visited your site but didn’t make the desired conversion. This will remind them of your brand and website, and will encourage an action in the future.