I've tried finding as many related galleries by searching variations of keywords including "wano umi", "wano", "wanwan sour", "wanwansour", "wanwansawa", "和野うみ", and "ワンワンサワー". Also tracked suggestions from the GTS Backlog page.

Some galleries with author "wano umi" on it are confused with the artist tag "wano", which I believe to be an entirely different artist based on art style and theme of manga. Galleries with "ワンワンサワー" or "和野うみ" are confirmed to be by "wano umi", whereas the other artist "wano" will have that name instead in their Japanese title.