Yes, you are right that some seeds could be toxic to Health, but i have had most of these seeds from personal experience. I know that is not enough prove since no two persons are the same, that's why i included the disclaimer at the end of the article. Also, seeds should not be consumed in large quantities. But here are the links like you suggested

Passion fruit seeds https://www.researchgate.net/publication/329363351_Nutritive_Values_of_Passion_Fruit_Passiflora_Species_Seeds_and_Its_Role_in_Human_Health

Papaya seeds
https://www.researchgate.net/publication/327745162_The_surprising_health_benefits_of_papaya_seeds_A_review

Watermelon seeds
https://www.researchgate.net/publication/323663320_Watermelon_Seeds_as_Food_Nutrient_CompositionPhytochemicals_and_Antioxidant_Activity

Avocado seeds
https://pubmed.ncbi.nlm.nih.gov/23448442/

African pear
https://www.researchgate.net/publication/49965758_The_Nutrient_Composition_of_Seeds_of_the_African_Pear_Dacryodes_edulis_and_its_Implications_for_Non-Ruminant_Nutrition

Pomegranate seeds
https://www.medicalnewstoday.com/articles/318384#tips

Orange seeds
https://www.nyoooz.com/features/health/incredible-healthy-and-surprising-benefits-of-orange-seeds.html/3289/