A few of the first ones that come to mind for me:
"Prem kiya hai, to bin mol bik jaao" - Ramanand Sagar's Ramayan, Shri Ram during Bharat Milaap. Bharat is shocked and disheartened that in spite of his love's 'victory' in the debate over Ayodhya's throne, Ram refuses to accept the kingdom without completing his exile. Shri Ram explains that true love has no expectations, i.e. if he truly loves Shri Ram, he will let him decide what's best even though it doesn't necessarily mean his own wish will come true. A lesson I think is just as applicable towards worldly relations as it is when trying to reconcile oneself with God's will.
"Tum to aaj ho, kal nahin rahoge. Mere prabhu to kal bhi the, aaj bhi hain, aur kal bhi rahenge!" - Anand Sagar's Ramayan, Sita in Ashok Vatika. Ravan is trying to convince her that he is worthy of her love by showing tricks with his sorcery. As she's envisioning Shri Ram in his Viraat Vishnu form, she's listing all the ways in which he is superior to Ravan and everyone else out there - basically quoting chapter 10 from the Gita. She concludes by telling him that his days are numbered, while Shri Ram will be with her forever. Very empowering moment.
(chuckling) "To jab main pehle hi Kuntiputra Arjun ka ho chuka hoon, Gandhaar Naresh, to Yuvraj Duryodhan ki kripaayen kaise sweekaar kar sakta hoon?" - BR Chopra's Mahabharat, Shri Krishna declines Duryodhan's hospitality just before the attempted peace treaty. Shakuni, Duryodhan, etc. are trying to butter him up in the famous "Duryodhan ghar meva tyaago, saag Vidur ghar khaayi" incident, and he keeps politely refusing. Shakuni and Karn ask why he's entangling political issues with their friendly gestures, since they are not his enemies, but the Pandavs'. They try to assert that their friendship with him is genuine, and he responds that if that were true, Duryodhan would have opted to have him (Krishna) on his side rather than accepting his divine army instead. Shakuni tries to defend that act by saying that Duryodhan only did so because he let his younger brother Arjun choose first, after which Krishna already belonged to him and the army was all that poor Duryodhan had left. To that, Shri Krishna laughs and gives the above comeback - that if I'm already his, then that's your answer to why I can't accept "generosity" from you! The response as well as the tone make this dialogue a memorable one among many others, because he mimics Shakuni's tone to hilarious effect 😆 He then proceeds onto a meaningful discourse on how he's actually on the side of Truth, not Arjun/Duryodhan... but still this part is what stuck out for me.
"Woh mera na hokar bhi jeevit to rahe, bas... mujhe aur kuch nahin chahiye!" - Ramanand Sagar's Shri Krishna, Devaki on being informed of Balram's birth when Nand Baba visits Mathura. He asks her if she'd like Rohini to visit so she can see the child, and she refuses and responds as quoted above. The ultimate in selflessness - and IMO the best response to all those janm denewaali vs. paalne wali cliches that undermine and sometimes even malign her character by making it seem as if she abandoned her child. She makes it clear here, that she is fine with missing out on both the joy of raising her divine children as well as the reputation of being their lucky mother, as long as her kids are safe and sound. In other words, her love is of the type Shri Ram describes in the very first dialogue I quoted in this post, from RSR - it is selfless and has no expectations.
I have many many more that I love from these 4 shows and some from others, I hope to share them with you guys every now and then. Please share your favorites as well, would love to read and reminisce about them!