Looking for Japanese Song Recommendation/Suggestion

I'm looking for Japanese song recommendation/suggestion similar to what I have listed below, similar in terms of being mellow, sentimental, or heart-breaking at most. Highly appreciated if you could mention both the title and the artist/singer. Thank you in advance.

ブランコ [Buranko] – 7!! [seven oops]
https://www.youtube.com/watch?v=LNOpdpzl2VE

オレンジ [Orange] – 7!! [seven oops]
https://www.youtube.com/watch?v=F-Cm-bmdLEY

オレンジ [Orange] Classic Version feat. Naoto – 7!! [seven oops]
https://www.youtube.com/watch?v=FxLfUHOmf0g

I Stay – 7!! [seven oops]
https://www.youtube.com/watch?v=3oMSJS0bRVk

紬 [Tsumugi] – 7!! [seven oops]
https://www.youtube.com/watch?v=12q9-usXgMk

[Shirushi] シルシ -LiVE is Smile Always〜PiNK & BLACK〜 in 日本武道館「ちょこドーナツ」- LiSA
https://www.youtube.com/watch?v=19UJBv6v0FI

プラネタリウム [Planetarium] – Otsuka Ai
https://www.youtube.com/watch?v=JhpwJNZSp2M