Better singers than Gura.
#1) Chikafuji Lisa
Probably the best singer on this list in terms of raw talent. She's only 19 years old, so she's not very refined as a singer. She loves listening to music in her streams, and loves finding really obscure bands.
https://www.youtube.com/watch?v=XhmWOL3uiyM#2) Amiya Aranha
Has been practicing singing for years, can play the guitar too. All hail the great singing spider.
https://www.youtube.com/watch?v=swJ3S-uav4Y&t=4230#3) Elira Pendora
Previously I would not consider her better than Gura. But recently she's been practicing a lot, so her recent karaokes sound better than ever.
https://files.catbox.moe/dkubxa.mp4#4) Enna Alouette
A professionally trained singer. She has some breathing problems unfortunately, but her vocal control is excellent.
https://www.youtube.com/watch?v=RRCk6VLtFNY#5) Ike Eveland
Many people aren't aware, he was actually hired for his singing talent. If only he sang more often.
https://www.youtube.com/watch?v=8NLvuakpnLM&t=2890Doubtless there's many many more I am not aware of.