This will NOT be a comprehensive list of all possible polyamorous Sonic ships, just ones I can think of, ones suggested by others, have posts, and within certain restrictions.
With respect that most of the cast is in their mid to late teens I will not be listing any ship with more than four years separating ANY other member; and for those younger than twelve only two years, with much less leeway for interpretations. Tikal and Shadow being sealed away for years does not count towards their ages because they didn't actually live them.
(These are my personal preferences and comfort levels for this blog, please don't harass anyone who does things outside this; ignore or block them and otherwise handle civilly if you have a problem somewhere.)
Sorted by: blog's main ship, ships containing those characters, character introduction. First listed will be this blog's tag.
Sonamyshad: Sonadamy, Sonshadamy, Shadsonamy, Soniamysha
Sonazamy: Sonamyblaze, Sonblazamy
Sonknuxadow*: Knuxsonadow, Knuxonadow, Sonuxadow, Sonshadknux,
Sonadilver: Sonadowilver, Shasonilver, Sonilvadow, Sonshadilver, Sonilveradow
Knuxadamy: Platonic Shadknuxamy
(*debating changing this one, while the most popular tag when I last checked, it is also someone's username.)