Some heavier groups that you might like are PassCode, Anthurium, BRATS, Shingeki, Seiko Oomori, PourLui, PIGGS, miscast, RAY, The Peggies, SOMOSOMO, Zsasz, I.D.&FlyLOOM...anything on WACKisIDOL label...lots of good up to the minute info on these types of artists is available on IdolOnChaos website which updates very often.
Trad idol groups i stan are Sakamichi Series groups (Nogizaka46, Keyakizaka46, Hinatazaka46) and Girls2 groups. =LOVE might appeal to the c-ute fan in you!
More "Otaku-ish" groups i stan are SAKA-SAMA, Appare! Harajuku, FES*TIVE, Dempagumi Inc, Nanahira (and literally everything else on Confetto Records), Rio Hiirage (AKA Rio-Rio), WASUTA, Yurumerumo, CY8ER, 星歴13夜.
R&B/girls' rap groups i recommend are Daoko, iri, Shachi, Asako Toki, Charisma.com, REOL, Lyrical School, She is Summer.
If you are feeling adventurous, please listen to KOTO, 3776 Minanaro (Chiyono Ide), 15GERM, 9999.999count stop, Little Emperor Syndrome, Ame to Kanmuri, amorecarina, Mariko Gotou, HamidaSystem, Oyasumi Hologram, MigmaShelter, mikinormu, Okinawa Electric Girl Saya, thisisnats, waq waq kingdom, ZOMBIE-CHANG, Wednesday Campanella
Well thats a lot lol...i hope you can check out these artists and maybe some you will like as much as i do! i also have a weekly idol podcast on archive.org as Black Tourmaline but there are no track or artist listings there.