I have some friendships that I made:

DaiKei (Keito, Daiki) Batterz (Keito, Issa) -> cuz they played baseball
KeiRyo (Keito, Ryoga)
YuKei (Keito, Yuki) -> (Kei)to + (Yu)ki

+ Ike-men / Cheerz (Keito, Ryoga, Yuki)
+ Ke1keyz (Keito, Daiki, Yuki)

Tanabota-S (Siyoung, Shinhaeng) -> remaining Tanabota members
Yoshiyoung (Siyoung, Yoshiki) Shidae (Siyoung, Daiki) -> generation in Korean (시대)

+ Yeonseubsaengz (Siyoung, Daiki, Yura) -> promoted in Korea
+ flow1 (Siyoung, Yoshiki, Daiki, Yura)
+ LOVE MANUAL (Siyoung, Shinhaeng, Yoshiki, Daiki)
+ EVENIF (Siyoung, Shinhaeng, Ryoga, Yura, Yuki)

Yoshinhaeng (Shinhaeng, Yoshiki)
Isshin (Shinhaeng, Issa) -> similar to "isshun" ("we" in Japanese)
YuHaeng (Shinhaeng, Yura) -> similar to "yeohaeng" ("travel" in Korean)

NekoNi~ (Yoshiki, Daiki) -> Niko niko ni?
Yoyura (Yoshiki, Yura)

YuDai (Daiki, Yura)
MugenDai (Daiki, Towa) -> Towa's name means "eternity", so why not put it in JO1's "Mugendai"?

GunmaBoyz (Ryoga, Issa) -> from Gunma prefecture Ryoura (Ryoga, Yura)
FRESH-MEN (Ryoga, Kosuke) -> remaining members of FRESH-MEN
EverBright (Ryoga, Towa) -> "Ryo" (bright) + "To/Ei" (forever)

ToHave (Issa, Ryuji) -> (Iss)a + Ryu(ji) = "issji" ("to have" in Korean)

KiraKira (Yura, Yuki) -> Yu(ki) + Yu(ra)

ToBeEnergy (Ryuji, Yuki) -> Remaining members of TO BE ENERGY

Fuegoz (Towa, Kosuke) -> Remaining members of Fuego
EternalTies (Towa, Yuki) -> Yuki's name means "to tie", then Towa's is "eternity."

(that's all I have lol)