I like childhood friend turn lover, especially in a high school setting.
Any recommendation is welcome.

I'll just recommend the ones I know (even the famous ones you probably have read already, since you like this trope).

Mousou Elektel
sugarmilk (one of the stories)
Tight Rope
Rin!
Itsuka Tomodachi ja Nakunaru to Shite mo
Me o Tojite 3-Byou
Bokura no Tsudzuki
Itsuka koi ni naru made and its sequel
Sono Mama de
Bokura ni Matsuwaru Et Cetera.
Harete Bokutachi wa and its sequel
Soba ni Oitene
Sukitte Iwasete?
Tomodachi Ijou no Koto, Shitai.
Kimi ni Ienai Koto ga Aru
Thoroughbred wa Nabikanai and its sequel
Replay (TSUKAHARA Saki)
Wootan to Fumi
Papa no Suki na Hito
in August

Galge no Sekai de Shinyuu ♂ ga Ore o Sukida to Iidashite!?
Okaeri Aureole
Kimi ni wa Todokanai.
Itsuka Tomodachi ja Nakunaru to Shite mo (2)

Dekoboko Sugar Days
Kakko Warukute Kakkoii Kimi
Kimi ga Inakeriya Iki mo Dekinai (work context)
Liquor & Cigarette (work context)
See You Later, Mermaid (they hang out outside of school)