Here is xda forum which exist before even vanced and revanced appeared, known for custom and modded android stuff. All threads and stuff shared here are highly monitored by Moderators of the xda. Also I believe I am kinda "trusted" person on xda. If you think something is shady please report me to the moderators.
These random sites you are looking at exist and appeared only to make money, or even be malware, you don't have "touch" with the owners of these sites who make these apks, you don't know who are they and they misleading the people by presenting as "official" especially the io site.
It's all about transparency and purpose. Read this.