Love Dodecahedron has these relationships to other tropes:

parents kids shares a parent with:
All Love Is Unrequited
Love Triangle
Unwanted Harem
Tenchi Solution
parent child
Love TriangleYandere Love Triangle
''Sibling Triangle
''Betty And Veronica
''Triang Relations
''Romantic False Lead
''Murder The Hypotenuse
''Two Person Love Triangle
You'll need to Get Known if you want to add or modify these relationships.