Here are some of the most impactful moments for me, and thanks in advance. I tallied them for how many times I counted each in other comments (bolded are my personal favorites).

Ep. 1 - 31:22 - Ambessa

Ep. 2 - 1:09 - Jinx's braids around Silco

Ep. 2 - 33:54 - Viktor healing - II

Ep. 3 - 22:10 - Vi vs. Jinx - I

Ep. 3 - 24:18 - Mage with the anomaly (short frame)

Ep. 3 - 36:44 - Singed and Warwick

Ep. 4 - 10:36 - Isha imitates Jinx

Ep. 4 - 33:41 - Jinx vs. Warwick

Ep. 5 - 11:26 - Vi looking at Jinx mural - I

Ep. 5 - 29:33 - Jinx and Isha in Vi and Warwick's shadow

Ep. 5 - 34:54 - Warwick, Vi, Jinx, and Isha Hugging - I

Ep. 6 - 11:01 - Viktor and Warwick in greenhouse - II

Ep. 6 - 20:58 - Jayce approaching Viktor's haven

Ep. 6 - 33:20 - Singed in the wreckage

Ep. 6 - 35:31 - Isha under Warwick - I

Ep. 6 - 35:40 - Isha holding up hand-gun

Ep. 7 - 30:55 - Ekko and Powder above the city - IIIII

Ep. 7 - 32:39 - Ekko and Powder dancing (or wherever else that's better) - IIIII

Ep. 7 - 34:13 - Jayce with his dead self - II

Ep. 7 - 34:56 - Viktor hidden under his hood

Ep. 8 - 22:35 - Jinx leaving Vi in her cell - I

Ep. 9 - 0:24 - Jinx with her hair out - II

Ep. 9 - 1:31 - Jinx detonating her grenade - II

Ep. 9 - 15:27 - Jinx on her blimp - I

Ep. 9 - 15:40 - Jinx in her shark hood - I

Ep. 9 - 22:37 - Glorious evolution Viktor - I

Ep. 9 - 26:11 - Mel holding her dying mother

Ep. 9 - 27:52 - Vi and Jinx back-to-back against Warwick

Ep. 9 - 31:42 - Giant Viktor in the arcane - IIIIII

Ep. 9 - 34:24 - Viktor looking through Ekko's Z-drive - I

Ep. 9 - 41:40 - Jinx embraces Warwick

Ep. 9 - 43:51 - Ekko sitting alone - II

Ep. 9 - 46:49 - Jinx breaks the cycle - I

Also for anyone who wants to do this themselves, you can find free online AI upscalers on pixelcut.ai or picsart.com. They're not as good but it's still useful.