Some cool other websites made by other people, or resources when it comes to UTAU!
Idoltrash Resources - List of Resamplers, wavtools, and other resources for UTAU/OpenUTAU
TUBS.WTF - Documentation of various reclists and voicebank types, namely in English by KLAD
ARPAsing Resources - Part of TUBS, a fanmade site to document every reclist and resource for the ARPAsing voicebank config created by Kanru Hua. Site created by KLAD
Utau.info - wiki that provides a masterlist of every possible UTAU resource, work in progress
Nyaonix - A great UTAU voicebank I'd recommend to any beginner! Nyaonix comes in the main Japanese voicebank formats: CV, VCV, and CVVC, perfect for people learning about UTAU. The CVVC also comes with loads of voice colors for maximum expressiveness.
Lunai Project - Great DIFFsinger AI project with many great vocalists such as Llane Crow and Denka Shaa. Unfortunately non-commercial if you're looking for commercial AI vocals.