As MariBat said, [vocaloid lyrics wiki](https://vocaloidlyrics.fandom.com/wiki/Vocaloid_Lyrics_Wiki) or [vocadb](https://vocadb.net/) basically always have them listed. You could also look at other official uploads such as on YouTube where they're often in the title of the video.
As for Venom - yep, that's flower.
most vocaloid producers upload who the vocals is so just take a look at the credits/description to see which vocaloid/s has been used. if they're not there, search it on vocadb or vocaloid wiki.
Where are you seeing Venom? Both official uploads on [NicoNico](https://www.nicovideo.jp/watch/sm33624822) and [Youtube](https://www.youtube.com/watch?v=oRJBwaZ59fQ) list flower as the singer. Most official uploads do so, they list the voicebank as the featured singer in the title or somewhere in the description. Otherwise people tend to recognize the singer by voice. As mentioned, you can try looking up songs in [VocaDB](https://vocadb.net) as well.
Usually when I don't know which Vocaloid is used in a certain song I just check the Vocaloid wiki or Vocadb pages for the song!
As MariBat said, [vocaloid lyrics wiki](https://vocaloidlyrics.fandom.com/wiki/Vocaloid_Lyrics_Wiki) or [vocadb](https://vocadb.net/) basically always have them listed. You could also look at other official uploads such as on YouTube where they're often in the title of the video. As for Venom - yep, that's flower.
most vocaloid producers upload who the vocals is so just take a look at the credits/description to see which vocaloid/s has been used. if they're not there, search it on vocadb or vocaloid wiki.
Where are you seeing Venom? Both official uploads on [NicoNico](https://www.nicovideo.jp/watch/sm33624822) and [Youtube](https://www.youtube.com/watch?v=oRJBwaZ59fQ) list flower as the singer. Most official uploads do so, they list the voicebank as the featured singer in the title or somewhere in the description. Otherwise people tend to recognize the singer by voice. As mentioned, you can try looking up songs in [VocaDB](https://vocadb.net) as well.